4.3.6: Improving the Quality of Decision-Making
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- Jamie Hammond and Western Technical College
- OpenStax
Learning Objectives
- Understand how a manager can improve his or her individual decision making.
Managers can use a variety of techniques to improve their decision-making by making better-quality decisions or making decisions more quickly. Table 2.1 summarizes some of these tactics.
| Type of Decision | Technique | Benefit |
| Programmed Decisions | Heuristics (mental shortcuts) | Saves Time |
| Satisficing (choosing first acceptable solution) | Saves Time | |
| Nonprogrammed Decisions | Systematically go through the six steps of the decision-making process | Improves quality |
| Talk to other people | Improves quality; generates more options, reduces bias | |
| Be creative | Improves quality; generates more options | |
| Conduct research; engage in evidence based decision-making | Improves quality | |
| Engage in critical thinking | Improves quality | |
| Think about the long term implications | Improves quality | |
| Consider the ethical implications | Improves quality |
Table 2.1(Attribution: Copyright Rice University, OpenStax, under CC-BY 4.0 license)
The Importance of Experience
An often overlooked factor in effective decision-making is experience. Managers with more experience have generally learned more and developed greater expertise that they can draw on when making decisions. Experience helps managers develop methods and heuristics to quickly deal with programmed decisions and helps them know what additional information to seek out before making a nonprogrammed decision.
Techniques for Making Better Programmed Decisions
In addition, experience enables managers to recognize when to minimize the time spent making decisions on issues that are not particularly important but must still be addressed. As discussed previously, heuristics are mental shortcuts that managers take when making programmed (routine, low-involvement) decisions. Another technique that managers use with these types of decisions is satisficing . When satisficing, a decision maker selects the first acceptable solution without engaging in additional effort to identify the best solution. We all engage in satisficing every day. For example, suppose you are shopping for groceries and you don’t want to overspend. If you have plenty of time, you might compare prices and figure out the price by weight (or volume) to ensure that every item you select is the cheapest option. But if you are in a hurry, you might just select generic products, knowing that they are cheap enough. This allows you to finish the task quickly at a reasonably low cost.
Techniques for Making Better Nonprogrammed Decisions
For situations in which the quality of the decision is more critical than the time spent on the decision, decision makers can use several tactics. As stated previously, nonprogrammed decisions should be addressed using a systematic process. We therefore discuss these tactics within the context of the decision-making steps. To review, the steps include the following:
- Recognize that a decision needs to be made.
- Generate multiple alternatives.
- Analyze the alternatives.
- Select an alternative.
- Implement the selected alternative.
- Evaluate its effectiveness.
Step 1: Recognizing That a Decision Needs to Be Made
Ineffective managers will sometimes ignore problems because they aren’t sure how to address them. However, this tends to lead to more and bigger problems over time. Effective managers will be attentive to problems and to opportunities and will not shy away from making decisions that could make their team, department, or organization more effective and more successful.
Step 2: Generating Multiple Alternatives
Often a manager only spends enough time on Step 2 to generate two alternatives and then quickly moves to Step 3 in order to make a quick decision. A better solution may have been available, but it wasn’t even considered. It’s important to remember that for nonprogrammed decisions, you don’t want to rush the process. Generating many possible options will increase the likelihood of reaching a good decision. Some tactics to help with generating more options include talking to other people (to get their ideas) and thinking creatively about the problem.
Talk to other people
Managers can often improve the quality of their decision-making by involving others in the process, especially when generating alternatives. Other people tend to view problems from different perspectives because they have had different life experiences. This can help generate alternatives that you might not otherwise have considered. Talking through big decisions with a mentor can also be beneficial, especially for new managers who are still learning and developing their expertise; someone with more experience will often be able to suggest more options.
Be creative
We don’t always associate management with creativity, but creativity can be quite beneficial in some situations. In decision-making, creativity can be particularly helpful when generating alternatives. Creativity is the generation of new or original ideas; it requires the use of imagination and the ability to step back from traditional ways of doing things and seeing the world. While some people seem to be naturally creative, it is a skill that you can develop. Being creative requires letting your mind wander and combining existing knowledge from past experiences in novel ways. Creative inspiration may come when we least expect it (in the shower, for example) because we aren’t intensely focused on the problem—we’ve allowed our minds to wander. Managers who strive to be creative will take the time to view a problem from multiple perspectives, try to combine information in news ways, search for overarching patterns, and use their imaginations to generate new solutions to existing problems. We’ll review creativity in more detail in Chapter 18.
Step 3: Analyzing Alternatives
When implementing Step 3, it is important to take many factors into consideration. Some alternatives might be more expensive than others, for example, and that information is often essential when analyzing options. Effective managers will ensure that they have collected sufficient information to assess the quality of the various options. They will also utilize the tactics described below: engaging in evidence-based decision-making, thinking critically, talking to other people, and considering long-term and ethical implications.
Do you have the best-quality data and evidence?
Evidence-based decision-making is an approach to decision-making that states that managers should systematically collect the best evidence available to help them make effective decisions. The evidence that is collected might include the decision maker’s own expertise, but it is also likely to include external evidence, such as a consideration of other stakeholders, contextual factors relevant to the organization, potential costs and benefits, and other relevant information. With evidence-based decision-making, managers are encouraged to rely on data and information rather than their intuition. This can be particularly beneficial for new managers or for experienced managers who are starting something new. (Consider all the research that Rubio and Korey conducted while starting Away).
Talk to other people
As mentioned previously, it can be worthwhile to get help from others when generating options. Another good time to talk to other people is while analyzing those options; other individuals in the organization may help you assess the quality of your choices. Seeking out the opinions and preferences of others is also a great way to maintain perspective, so getting others involved can help you to be less biased in your decision-making (provided you talk to people whose biases are different from your own).
Are you thinking critically about the options?
Our skill at assessing alternatives can also be improved by a focus on critical thinking . Critical thinking is a disciplined process of evaluating the quality of information, especially data collected from other sources and arguments made by other people, to determine whether the source should be trusted or whether the argument is valid.
An important factor in critical thinking is the recognition that a person’s analysis of the available information may be flawed by a number of logical fallacies that they may use when they are arguing their point or defending their perspective. Learning what those fallacies are and being able to recognize them when they occur can help improve decision-making quality. See Table 2.2 for several examples of common logical fallacies.
| Name | Description | Examples | Ways to Combat This Logical Fallacy |
| Non sequitur (does not follow) | The conclusion that is presented isn’t a logical conclusion or isn’t the only logical conclusion based on the argument(s). |
Our biggest competitor is spending more on marketing than we are. They have a larger share of the market. Therefore, we should spend more on marketing. The unspoken assumption: They have a larger share of the market BECAUSE they spend more on marketing |
In this example, you should ask:Are there any other reasons, besides their spending on marketing, why our competitor has a larger share of the market? |
| False cause | Assuming that because two things are related, one caused the other | “Our employees get sick more when we close for holidays. So we should stop closing for holidays.” |
This is similar to non sequitur; it makes an assumption in the argument sequence.
In this case, most holidays for which businesses close are in the late fall and winter (Thanksgiving, Christmas), and there are more illnesses at this time of year because of the weather, not because of the business being closed. |
| Ad hominem (attack the man) | Redirects from the argument itself to attack the person making the argument | “You aren’t really going to take John seriously, are you? I heard his biggest client just dropped him for another vendor because he’s all talk and no substance.” The goal:if you stop trusting the person, you’ll discount their argument. |
|
| Genetic fallacy | You can’t trust something because of its origins |
“This was made in China, so it must be low quality.” “He is a lawyer, so you can’t trust anything he says.” |
This fallacy is based on stereotypes.  Recognize this for what it is—an attempt to prey on existing biases. |
| Appeal to tradition | If we have always done it one particular way, that must be the right or best way | “We’ve always done it this way.” “We shouldn’t change this; it works fine the way it is.” |
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| Bandwagon approach | If the majority of people are doing it, it must be good. |
“Everybody does it.” “Our customers don’t want to be served by people like that.” |
|
| Appeal to emotion | Redirects the argument from logic to emotion | “We should do it for [recently deceased] Steve; it’s what he would have wanted.” |
|
Table 2.2(Attribution: Copyright Rice University, OpenStax, under CC-BY 4.0 license)
Have you considered the long-term implications?
A focus on immediate, short-term outcomes—with little consideration for the future—can cause problems. For example, imagine that a manager must decide whether to issue dividends to investors or put that money into research and development to maintain a pipeline of innovative products. It’s tempting to just focus on the short-term: providing dividends to investors tends to be good for stock prices. But failing to invest in research and development might mean that in five years the company is unable to compete effectively in the marketplace, and as a result the business closes. Paying attention to the possible long-term outcomes is a crucial part of analyzing alternatives.
Are there ethical implications?
It’s important to think about whether the various alternatives available to you are better or worse from an ethical perspective, as well. Sometimes managers make unethical choices because they haven’t considered the ethical implications of their actions. In the 1970s, Ford manufactured the Pinto, which had an unfortunate flaw: the car would easily burst into flames when rear-ended. The company did not initially recall the vehicle because they viewed the problem from a financial perspective, without considering the ethical implications. 10 People died as a result of the company’s inaction. Unfortunately, these unethical decisions continue to occur—and cause harm—on a regular basis in our society. Effective managers strive to avoid these situations by thinking through the possible ethical implications of their decisions. The decision tree in Exhibit 2.6 is a great example of a way to make managerial decisions while also taking ethical issues into account.
Thinking through the steps of ethical decision-making may also be helpful as you strive to make good decisions. James Rest’s ethical decision-making model 11 identifies four components to ethical decision making:
- Moral sensitivity—recognizing that the issue has a moral component;
- Moral judgment—determining which actions are right vs. wrong;
- Moral motivation/intention—deciding to do the right thing; and
- Moral character/action—actually doing what is right.
Note that a failure at any point in the chain can lead to unethical actions! Taking the time to identify possible ethical implications will help you develop moral sensitivity, which is a critical first step to ensuring that you are making ethical decisions.
Once you have determined that a decision has ethical implications, you must consider whether your various alternatives are right or wrong—whether or not they will cause harm, and if so, how much and to whom. This is the moral judgment component. If you aren’t sure about whether something is right or wrong, think about how you would feel if that decision ended up on the front page of a major newspaper. If you would feel guilty or ashamed, don’t do it! Pay attention to those emotional cues—they are providing important information about the option that you are contemplating.
The third step in the ethical decision-making model involves making a decision to do what is right, and the fourth step involves following through on that decision. These may sound, but consider a situation in which your boss tells you to do something that you know to be wrong. When you push back, your boss makes it clear that you will lose your job if you don’t do what you’ve been told to do. Now, consider that you have family at home who rely on your income. Making the decision to do what you know is right could come at a substantial cost to you personally. In these situations, your best course of action is to find a way to persuade your boss that the unethical action will cause greater harm to the organization in the long-term.
Step 4: Selecting an Alternative
Once alternative options have been generated and analyzed, the decision maker must select one of the options. Sometimes this is easy—one option is clearly superior to the others. Often, however, this is a challenge because there is not a clear “winner” in terms of the best alternative. As mentioned earlier in the chapter, there may be multiple good options, and which one will be best is unclear even after gathering all available evidence. There may not be a single option that doesn’t upset some stakeholder group, so you will make someone unhappy no matter what you choose. A weak decision maker may become paralyzed in this situation, unable to select among the various alternatives for lack of a clearly “best” option. They may decide to keep gathering additional information in hopes of making their decision easier. As a manager, it’s important to think about whether the benefit of gathering additional information will outweigh the cost of waiting. If there are time pressures, waiting may not be possible.
Recognize that perfection is unattainable
Effective managers recognize that they will not always make optimal (best possible) decisions because they don’t have complete information and/or don’t have the time or resources to gather and process all the possible information. They accept that their decision-making will not be perfect and strive to make good decisions overall. Recognizing that perfection is impossible will also help managers to adjust and change if they realize later on that the selected alternative was not the best option.
Talk to other people
This is another point in the process at which talking to others can be helpful. Selecting one of the alternatives will ultimately be your responsibility, but when faced with a difficult decision, talking through your choice with someone else may help you clarify that you are indeed making the best possible decision from among the available options. Sharing information verbally also causes our brains to process that information differently, which can provide new insights and bring greater clarity to our decision-making.
Step 5: Implementing the Selected Alternative
After selecting an alternative, you must implement it. This may seem too obvious to even mention, but implementation can sometimes be a challenge, particularly if the decision is going to create conflict or dissatisfaction among some stakeholders. Sometimes we know what we need to do but still try to avoid actually doing it because we know others in the organization will be upset—even if it’s the best solution. Follow-through is a necessity, however, to be effective as a manager. If you are not willing to implement a decision, it’s a good idea to engage in some self-reflection to understand why. If you know that the decision is going to create conflict, try to think about how you’ll address that conflict in a productive way. It’s also possible that we feel that there is no good alternative, or we are feeling pressured to make a decision that we know deep down is not right from an ethical perspective. These can be among the most difficult of decisions. You should always strive to make decisions that you feel good about—which means doing the right thing, even in the face of pressures to do wrong.
Step 6: Evaluating the Effectiveness of Your Decision
Managers sometimes skip the last step in the decision-making process because evaluating the effectiveness of a decision takes time, and managers, who are generally busy, may have already moved on to other projects. Yet evaluating effectiveness is important. When we fail to evaluate our own performance and the outcomes of our decisions, we cannot learn from the experience in a way that enables us to improve the quality of our future decisions.
Attending fully to each step in the decision-making process improves the quality of decision-making and, as we’ve seen, managers can engage in a number of tactics to help them make good decisions. Take a look at the Ethics in Practice box to see an example of how one particular manager puts these techniques into practice to make good decisions.
Ethics In Practice
Rob Ault, Project Manager, Bayside Community Church
Bradenton, Florida
When it comes to decision-making, ethical dilemmas require particular care. Because managers make many decisions, it should not be surprising that some of those decisions will have ethical implications. With multiple stakeholders to consider, sometimes what is best for one group of stakeholders is not what is best for others. I talked to Rob Ault about his experiences with ethical dilemmas over the course of his career. Rob has been in managerial roles for over 25 years, since he was 19 years old. He told me that he had experienced a number of ethical dilemmas in that time.
Rob has spent most of his career working for for-profit organizations, and for about half of that time he has worked in a union environment. What he has found most frustrating, regardless of environment, was when it was clear to him what was right, but what was right conflicted with what his boss was telling him to do. This included a situation in which he felt an employee should be fired for misbehavior (but wasn’t), as well as situation in which he was asked to fire someone undeservedly. What we mostly talked about, though, was his process. How did he go about making decisions in these challenging situations?
Rob clearly stated that his approach to these situations has changed with experience. What he did early in his career is not necessarily what he would do now. He said that it takes experience and some maturity to recognize that, as a leader, the decisions you make affect other people’s lives. He also explained that a starting point for the decision-making process is always a recognition of the fact that you have been hired to generate a benefit for your company. So a manager’s decisions need to come from the perspective of what is going to be in the best long-term interest of the organization (in addition to what is morally right). This isn’t always easy, because short-term consequences are much easier to observe and predict.
I asked Rob who he talked to prior to making decisions in situations with an ethical component. Rob told me that he felt one of the most important things you should do as a leader is to intentionally create and build relationships with people you trust in the organization. That way you have people you know you can talk to when difficult situations come up. He was very clear that you should always talk to your boss, who will tend to have a broader understanding of what is going on in the context of the larger organization. He also told me that he liked to talk to his father, who happened to work in human resource management for a large Fortune 500 organization. His father was always helpful in providing the perspective of how things were likely to play out long-term if one person was allowed to bend the rules. Rob realized eventually that the long-term consequences of this were almost always negative: once one person is allowed to misbehave, others find out about it and realize that they can do the same thing without repercussions. Rob also seeks out the opinions of other individuals in the organization before reaching decisions with an ethical component; he told me that when he worked in a union environment, he tried to make sure he had a good relationship with the union steward, because it was helpful to get the perspective of someone who was committed to the side of the employee.
The biggest ethical dilemma Rob faced was one that he actually couldn’t talk to me about. He disagreed with what he was being asked to do, and when it was clear that he had no other choice in the matter, he quit his job rather than do something he felt wasn’t right. He accepted a severance package in exchange for signing a nondisclosure agreement, which is why he can’t share any details . . . but it was clear from our conversation that he feels he made the right choice. That particular ethical dilemma makes it clear how challenging managerial decision-making can sometimes be.
Discussion Questions
- If you were faced with an ethical dilemma, from whom would you seek advice?
- Describe some decisions that might be good for an organization’s profitability in the short-term, but bad for the organization in the long-term.
- What factors would you take into consideration if you were thinking about leaving your job rather than do something unethical?
Concept Check
- Explain what satisficing is and when it may be a good strategy.
- What are the six steps in the decision-making process?
- What are the four steps involved in ethical decision-making?
References
10. Linda K. Trevino & Michael E. Brown. 2004. Managing to be ethical: Debunking five business ethics myths. Academy of Management Executive , 18: 69-81.
11. James R. Rest. 1986. Moral development: Advances in research and theory . Praeger Publishers.


2.S: Periodic Properties of the Elements (Summary)
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7.1: Development of the Periodic Table
- 1869: Dmitri Mendeleev (Russia) and Lothar Meyer (Germany) publish nearly identical schemes for classifying the elements
- Both had arranged the elements in order of increasing atomic weights
- Mendeleev predicted the existence and properties of Germanium (Ge) and Gallium (Ga). When they were discovered, their properties were found to closely match those predicted by Mendeleev
- 1913: Henry Moseley discovers concept of atomic numbers. Observed that frequencies of Xrays were different for each element. Was able to arrange these frequencies in order by assigning each element a unique whole number, which he called the atomic number
7.2: Effective Nuclear Charge
- Orbitals with the same value of n are referred to as a shell
- When looking at a radial electrondensity graph, the maxima (peaks) designate the areas with the higher probabilities of finding electrons
- The 1s shell in Argon is closer to the nucleus than that of Helium. This is because both 1s shells are the only ones not shielded from the nucleus by other electrons. However, since Argon has a stronger nuclear charge, it can attract its electrons more easily
- radial electron density – probability of finding the electron at a particular distance from the nucleus
- as nuclear charge increases, 1s shells pulled closer to nucleus
7.3: Sizes of Atoms and Ions
Atomic radius : radius of an atom of a given element
- Within each group, the atomic radius tends to increase going from top to bottom
- Within each period, the atomic radius tends to decrease moving left to right
Two factors determine the size of the outermost orbital
- Its principal quantum number (as it increases, the size of the orbital increases)
- The effective nuclear charge (reduces the size of the orbital by pulling electrons closer)
Atomic Sizes
- atomic radius – estimation of radius of atoms
- estimate by assuming that atoms are spheres that touch each other
- atomic radius increases down a group, decrease down row
- atomic radius affected by principal quantum number and effective nuclear charge
- increase principal quantum number, increases size of orbital
- increase effective nuclear charge, reduces size or orbital
7.4: Ionization Energy
Ionization energy : energy required to remove an electron from a gaseous atom when the atom is in its ground state.
- first ionization energy – energy needed to remove the first electron
- second ionization energy – energy needed to remove second electron
- the greater ionization energy, harder it is to remove electrons
- The first ionization energy, I 1 , is the energy needed to remove the first electron. The second ionization energy, I 2 , removes the second electron, and so on. The HIGHER the ionization energy, the MORE DIFFICULT it is to remove an electron. Every element exhibits a large increase in ionization energy when electrons are removed from its noblegas core. The inner electrons are too tightly bound to the nucleus to be lost from the atom or even shared with another atom
\[I_1< I_2 < I_3 \nonumber \]
- Positive nuclear charge remains same, number electrons decreases -> effective nuclear charge increases
- Greater effective nuclear charge, greater energy required to remove electron
- Sharp increase in ionization energy when inner-shell electron removed
- Only outer most electrons involved in sharing and transfer of electrons in bonding and reactions
Periodic Trends in Ionization Energies
- Within each period, I 1 generally increases with increasing atomic number. The alkali metals show the lowest ionization energy in each row, and the noble gases the highest
- Within each group, ionization energy generally decreases with increasing atomic number.
- Energy needed to remove electrons from outer shell depends on nuclear charge and average distance between of the electron from the nucleus
- As we move across a period, there is both an increase in effective nuclear charge and a decrease in atomic radius, causing the ionization energy to increase
- As we move down a column, the atomic radius increases, while the effective charge remains essentially constant. Thus, the attraction between the nucleus and the electron decreases in this direction, causing the ionization energy to decrease.
7.5: Electron Affinities
- Electron affinity : energy change that occurs when an electron is added to a gaseous atom or ion
- For most neutral atoms and for all positively charged ions, energy is released when an electron is added
- The greater the attraction between the species and the added electron, the more exothermic the process
- On the other hand, adding an electron to anions and to some atoms makes them unstable.
- The general trend for electron affinity is to become increasingly negative (stronger binding of electrons) as we move across each period toward the halogens. The halogens have the most negative electron affinities since they are one electron short of noblegas configuration
- Electron affinities do not change greatly as we go down a group
7.6: Metals, Nonmetals, and Metalloids
| Metallic elements | Nonmetallic elements |
|---|---|
| Distinguishing luster | Nonlustrous; various colors |
| Malleable and ductile as solids | Solids are usually brittle; may be hard or soft |
| Good thermal and electrical conductivity | Poor conductors of heat and electricity |
| Most metallic oxides are basic, ionic solids | Most nonmetallic oxides are molecular, acidic compounds |
| Exist in aqueous solution mainly as cations | Exist in aqueous solution mainly as anions or oxyanions |
Metals
- See properties above. All are solids at room temperature except mercury, which is a liquid.
- Metals tend to have low ionization energies and are consequently oxidized (lose electrons) when they undergo chemical reaction.
- Compounds of metals with nonmetals tend to be ionic substances
- Most metals are basic oxides (oxide that either reacts with water to form a base or reacts with an acid to form a salt and water)
Nonmetals
- Generally have lower melting points than those of metals.
- Seven nonmetals exist as diatomic molecules under ordinary conditions (H 2 , N 2 , O 2 , F 2 , Cl 2 , Br 2 , I 2 ). Bromine is liquid; Iodine is a volatile solid, the rest are gases. The remaining nonmetals are solids.
- Nonmetals, in reacting with metals, tend to gain electrons and become anions
- Compound composed entirely of nonmetals are molecular substances
- Most nonmetals are acidic oxides (oxide that forms acid when added to water; soluble nonmetal oxides are acidic oxides)
Metalloids
- Have properties intermediate between those of metals and nonmetals. May have some metallic properties but lack others.
- Several metalloids are electrical semiconductors
Trends in Metallic and Nonmetallic Character
Metallic character : the extent to which an element exhibits the physical and chemical properties characteristic of metals, for example, luster, malleability, ductility, and good thermal and electrical conductivity.
- Metallic character is strongest for the elements in the leftmost part of the periodic table and tends to decrease as we move to the right in any period
- Within any group of representative elements, the metallic character increases progressively from top to bottom
7.7: Group Trends for the Active Metals
Group 1: The Alkali Metals
- Metallic properties; silvery, metallic luster, high thermal and electrical conductivity
- Low densities and melting points; increasing atomic radius and decreasing ionization energy as we move down the family
- Lowest I 1 values of the elements, which reflects the ease with which their outer electrons can be removed. This makes the alkali metals very reactive, readily losing one electron.
- In the hydrides of the alkali metals (LiH, NaH, and so forth), hydrogen is present as H, called the hydride ion .
- The alkali metals react vigorously with water, producing hydrogen gas and solutions of alkali metal hydroxides (very exothermic).
Group 2: The Alkaline Earth Metals
- Solids, typical metallic properties, denser and harder than alkali metals (also melt at higher temperatures)
- Less reactive than alkali metals (have slightly higher ionization energy)
- Ease with which the elements lose their electrons increases as we move down the family
7.8: Group Trends for Selected Nonmetals
Hydrogen
- Hydrogen is a nonmetal, which occurs as a diatomic gas under normal conditions
- Its ionization energy is considerably higher (due to lack of shielding, and thus higher Z eff ) thatn the metals and is more like the nonmetals
- Hydrogen generally reacts with other nonmetals to form molecular compounds (typically highly exothermic)
- Hydrogen reacts with active metals to form metal hydrides that contain the H hydride ion
- Hydrogen can also lose an electron to yield the aqueous H + ion
Group 16: The Oxygen Family
- As we proceed down group 6A, the increase in metallic character is clearly evident
- Allotropes : different forms of the same element in the same state (ie: O 2 and O 3 )
- Oxygen has a great tendency to attract electrons from other elements ("oxidize" them)
- Oxygen in combination with metals is almost always present as the oxide, O 2 ion, which has noblegas configuration and is particularly stable
- Sulfur is the second most important element in the 6A group. It also exists in several allotropic, the most common and stable being S 8 .
- Sulfur also has a great tendency to gain electrons from other elements to form sulfides
- Because Sulfur is below Oxygen, its tendency to form sulfide anions is not is not as great as that of Oxygen to form oxide ions
Group 17: The Halogens
- All halogens are typical nonmetals. Their melting and boiling points increase with increasing atomic numbers
- Fluorine and Chlorine are gases at room temperature, Bromine is a liquid, and Iodine is a solid
- The halogens have among the most negative electron affinities; they have a great tendency to gain electrons.
- Fluorine and Chlorine are the most reactive. Fluorine removes electrons from almost any substance, even water, and usually very exothermically.
- Halogens react with most metals to form ionic halides and with Hydrogen to form gaseous hydrogen halides.
Group 18: The Noble Gases
- All noble gases are monoatomic (single atom)
- All have large first ionization energies, with a decrease as we go down the group
- Until the early 1960’s, they were called inert gases because they were thought to be incapable of forming chemical compounds.
- Only noblegas compounds known today are: XeF 2 , XeF 4 , XeF 6 , and KrF 2


Where Does the Money Go?
Most people aren’t really sure where a lot of their money goes. Take this survey to see how much you remember about how you have spent money recently.
Do your best to remember how much you have spent in the last thirty days in each of the following categories
:
Now be honest with yourself: is this
really
all you spent on these items? Most of us forget small, daily kinds of purchases or underestimate how much we spend on them—especially when we pay with cash.
You’ll notice also that this list does not include essential spending for things like room and board or an apartment and groceries, utilities, college tuition and books, and so on. The greatest potential for cutting back on spending is in the area of optional things.
Spending on Essentials, Spending on Optionals
More people get into financial trouble because they’re spending too much than because they’re making (or receiving) too little. While spending may seem a simple matter—“I need to buy this, I’d like to buy that”—it’s actually very complex. America is a consumer society, and we’re deluged by advertisements promising that we’ll be happier, more successful, better liked by more people, sexier, and everything else if only we buy
this
. Companies have spent billions of dollars researching how to manipulate our buying behavior. No wonder it’s so tough to resist these pressures!
Why does a person feel compelled to buy fast food for lunch, or a new CD with a song they just heard on the radio, or a new video game a friend says is so good, or a new article of clothing? We owe it to ourselves to try to understand our own attitudes about money and spending. Here’s a good place to start:
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Having money or not having money doesn’t define who you are.
Your real friends will think no less of you if you make your own lunch and eat it between classes or take the bus to campus rather than drive a new car.

Some people always have more money than others and spend more. Resist any feeling that your friends who are big spenders are the norm. Don’t feel you have to go along with whatever expensive activities they propose just so you fit in.
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A positive attitude leads to success.
Learn to relax and not get stressed out about money. If you need to make changes in how you spend money, view this as an exciting accomplishment, not a depressing fact. Feel good about staying on a budget and being smart about how you spend your money.
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Be realistic about what you can accomplish.
Most students have financial problems, and they don’t just go away by waving a magic wand of good intentions. If your budget reveals you don’t have enough money even while working and carefully controlling your spending, you may still need a student loan or larger changes in your lifestyle to get by. That’s OK—there are ways to deal with that. But if you unrealistically set your sights so high about spending less and saving a lot, you may become depressed or discouraged if you don’t meet your goals.
Before you can make an effective budget, you need to look at what you’re spending money on now and consider what’s essential and what’s optional. Essential costs are the big things:
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Room and board or rent/mortgage, utilities, and groceries
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College tuition, fees, textbooks, supplies
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Transportation
-
Insurance (health insurance, car insurance, etc.)
-
Dependent care if needed
-
Essential personal items (
some
clothing, hygiene items, etc.)
These things are sometimes called fixed costs, but that term can be misleading. If you have the option to move to a less expensive apartment that is smaller or a few blocks farther away, you can partly control that cost, so it’s not really “fixed.” Still, for most people, the real savings come from spending less on optional things.
Look back at the amounts you wrote in the earlier exercise “Where Does the Money Go?” These things are “optional” expenses—you can spend more or less on them as you choose. Most people spend by habit, not really thinking about where their money goes or how quickly their spending adds up. If you knew you were spending more than a thousand dollars a year on coffee you buy every day between classes, would that make you think twice? Or another thousand on fast food lunches rather than taking a couple minutes in the morning to make your lunch? When people actually start paying attention to where their money goes, most are shocked to see how the totals grow. If you can save a few thousand dollars a year by cutting back on just the little things, how far would that go to making you feel much better about your finances?
Following are some general principles for learning to spend less. The “Tips for Success” then lists specific ways you can try to follow these principles in your daily life.
Remember, spending money doesn’t define who you are!
-
Be aware of what you’re spending.
Carry a small notebook and write down everything—
everything
—you spend for a month. You’ll see your habits and be able to make a better budget to take control.
-
Look for alternatives.
If you buy a lot of bottled water, for example, you may feel healthier than people who drink soft drinks or coffee, but you may be spending hundreds of dollars a year on something that is virtually free! Carry your own refillable water bottle and save the money.
-
Plan ahead to avoid impulse spending.
If you have a healthy snack in your backpack, it’s much easier to not put a dollar in a vending machine when you’re hungry on the way to class. Make a list before going grocery shopping and stick to it. Shopping without a list usually results in buying all sorts of unneeded (and expensive) things that catch your eye in the store.
-
Be smart.
Shop around, compare prices, and buy in bulk. Stopping to think a minute before spending is often all it takes.
Tips for Success: Spending Less
-
Make your own lunches and snacks.
-
Read newspapers and magazines online or in the library.
-
Cancel cable television and watch programs online for free.
-
Use free campus and local Wi-Fi spots and cancel your home high-speed Internet connection.
-
Buy generic products instead of name brands.
-
Shop at thrift stores and yard sales.
-
Pay with cash instead of a credit card.
-
Cancel your health club membership and use a free facility on campus.
-
Compare prices online.
-
Avoid ATM fees by finding a machine on your card’s network (or change banks); avoid checking account monthly fees by finding a bank with free checking.
-
Get cash from an ATM in small amounts so you never feel “rich.”
-
With larger purchases, postpone buying for a couple days (you may find you don’t “need” it after all).
-
Look for free fun instead of movies and concerts—most colleges have frequent free events.

-
Use good study skills to avoid failing a class—paying to retake a course is one of the quickest ways to get in financial trouble!
Managing a Budget
Budgeting involves analyzing your income and expenses so you can see where your money is going and making adjustments when needed to avoid debt. At first budgeting can seem complex or time consuming, but once you’ve gone through the basics, you’ll find it easy and a very valuable tool for controlling your personal finances.
Why create and manage a budget? Going to college changes your financial situation. There are many new expenses, and you likely don’t know yet how your spending needs and habits will work out over the long term. Without a budget, it’s just human nature to spend more than you have coming in, as evidenced by the fact that most Americans today are in debt. Debt is a major reason many students drop out of college. So it’s worth it to go to the trouble to create and manage a budget.
Managing a budget involves three steps:
-
Listing all your sources of income on a monthly basis.
-
Calculating all your expenditures on a monthly basis.
-
Making adjustments in your budget (and lifestyle if needed) to ensure the money isn’t going out faster than it’s coming in.
Tracking Income
Many college students receive money or financial assistance from a number of sources. To track income in a monthly budget, consider all your sources of funds and convert them to a monthly number. For example, you may receive a student loan once during the year or you may work more in the summer and save up money then. To calculate your monthly projected income, add up your income sources and divide that number by the number of months you will be using the income. For example, if you have saved $4,800 that you can spend over two years of college, divide the $4,800 by twenty-four months to arrive at a monthly income of $200 from those savings. Do the same with scholarship grants, student loans, monetary gifts, and so on.
If some of your college costs are being paid directly by parents or others, do not include that money in your budget as either income or an expense. Base your monthly budget on just those funds and expenses that involve you directly.
Use Table 11.1 “Monthly Income and Funds” to record and total all your income on a monthly basis. If you must estimate some sources, estimate low rather than high; it’s a bad trap to assume you’ll have more money coming in than you actually do—that’s a real budget buster.
Table 11.1 Monthly Income and Funds
income
|
Source of Income/Funds
|
Amount in Dollars
|
|
Job income/salary (take-home amount)
|
|
|
Funds from parents/family/others
|
|
|
Monthly draw from savings
|
|
|
Monthly draw from financial aid
|
|
|
Monthly draw from student/other loans
|
|
|
Other income source: ________________
|
|
|
Other income source: ________________
|
|
|
Other income source: ________________
|
|
|
Total Monthly Incoming:
|
|
Tracking Expenses
Tracking expenditures is more difficult than tracking income. Some fixed expenses (tuition, rent, etc.) you should already know, but until you’ve actually written down everything you spend in a typical month, it’s hard to estimate how much you’re really spending on cups of coffee or smoothies between class, groceries, entertainment, and the like. The best way to itemize this side of your budget is to write down everything you spend—
everything
, every bottle of water and cookie, coins into parking meters, and so forth—for a full month. Then you can total up the different categories of expenses more realistically. We urge you to immediately start writing everything down in a small notebook you carry with you. You may be astonished how small purchases add up.
While you’re writing this down for a month, go ahead and work through the expenditure half of your budget, using Table 11.2 “Monthly Expenditures”. Set aside an hour or two to look through your past financial records, checkbook register and debit card transactions, past utility bills, credit card statements, and so on to get the numbers to put in your expenses budget. Make estimates when you have to, but be honest with yourself and don’t underestimate your usual spending. There will be plenty of time down the road to adjust your budget—but don’t start out with an unrealistic plan. Write “est” (for estimated”) next to numbers in your budget that you’re guessing at.
Once you have listed your routine expenditures using Table 11.2 “Monthly Expenditures”, write out your own budget categories that fit how
you
actually spend money. Everyone is unique, and you want your budget to be easy to use for your own life and habits.
As noted previously with income, if some of your expenses are paid directly by others, do not include them here. Base your monthly budget on just those funds and expenses that involve you directly.
Table 11.2 Monthly Expenditures
|
Expenditures
|
Amount in Dollars
|
|
Tuition and fees (1/12 of annual)
|
|
|
Textbooks and supplies (1/12 of annual)
|
|
|
Housing: monthly mortgage, rent, or room and board
|
|
|
Home repairs
|
|
|
Renter’s insurance
|
|
|
Property tax
|
|
|
Average monthly utilities (electricity, water, gas, oil)
|
|
|
Optional utilities (cell phone, Internet service, cable television)
|
|
|
Dependent care, babysitting
|
|
|
Child support, alimony
|
|
|
Groceries
|
|
|
Meals and snacks out (including coffee, water, etc.)
|
|
|
Personal expenses (toiletries, cosmetics, haircuts, etc.)
|
|
|
Auto expenses (payments, gas, tolls) plus 1/12 of annual insurance premium—or public transportation costs
|
|
|
Loan repayments, credit card pay-off payments
|
|
|
Health insurance (1/12 of annual)
|
|
|
Prescriptions, medical expenses
|
|
|
Entertainment (movies, concerts, nightlife, sporting events, purchases of CDs, DVDs, video games, etc.)
|
|
|
Bank account fees, ATM withdrawal fees, credit card finance charges
|
|
|
Newspapers, magazines, subscriptions
|
|
|
Travel, day trips
|
|
|
Cigarettes, smokeless tobacco
|
|
|
Beer, wine, liquor
|
|
|
Gifts
|
|
|
Hobbies
|
|
|
Major purchases (computer, home furnishings) (1/12 of annual)
|
|
|
Clothing, dry cleaning
|
|
|
Memberships (health clubs, etc.)
|
|
|
Pet food, veterinary bills, and so on
|
|
|
Other expenditure:
|
|
|
Other expenditure:
|
|
|
Other expenditure:
|
|
|
Other expenditure:
|
|
|
Other expenditure:
|
|
|
Total Monthly Outgoing:
|
|
Balancing Your Budget
Now comes the moment of truth: compare your total monthly incoming with your total monthly outgoing. How balanced is your budget at this point? Remember that you estimated some of your expenditures. You can’t know for sure until you actually track your expenses for at least a month and have real numbers to work with.
What if your spending total is higher than your income total? The first step is to make your budget work on paper. Go back through your expenditure list and see where you can cut. Remember, college students shouldn’t try to live like working professionals. Maybe you are used to a nice haircut every month or two—but maybe you can go to a cheaper place or cut it yourself. There are dozens of ways to spend less, as suggested earlier.
The essential first step is to make your budget balance on paper
.
Then your job is to live within the budget. It’s normal to have to make adjustments at first. Just be sure to keep the overall budget balanced as you make adjustments. For example, if you find you must spend more for textbooks, you may decide you can spend less on eating out—and subtract the amount from that category that you add to the textbook category. Get in the habit of thinking this way instead of reaching for a credit card when you don’t have enough in your budget for something you want or need.
Don’t be surprised if it takes several months to make the budget process work. Be flexible, but stay committed to the process and don’t give up because it feels like to too much work to keep track of your money. Without a budget, you may have difficulty reaching your larger goal: taking control of your life while in college.
Budgeting on Your Computer
If you are good at Excel or another spreadsheet program, you can create your own budget in a spreadsheet that allows you to monitor your income and expenditures month to month, with the calculations done for you. Other budget calculators can be found online. Figure 12.8 “Simple Online Budget Calculator” shows a simple online budget calculator. The categories are general, but you can add up your numbers from Table 11.2 “Monthly Expenditures” in these categories and enter them in the online budget form, which then does the calculations for you.
Most college students can do well with a simple budget that helps you track monthly income and expenditures so that you can make adjustments as needed. If your financial life is more complicated or you would enjoy full financial tracking and control using your computer, a software program like Quicken has all the power you need and can download your banking and credit card records to easily track categories of expenses over time. A free online budget and tracking system is available at Mint.com.
What If Your Budget Doesn’t Work?
Your budget may be unbalanced by a small amount that you can correct by reducing spending, or it may have a serious imbalance. If your best efforts fail to cut your expenditures to match your income, you may have a more serious problem, unless you plan in advance to manage this with student loans or other funds.
First, think about how this situation occurred. When you decided to go to college, how did you plan to finance it? Were you off in your calculations of what it would cost, or did you just hope for the best? Are you still committed to finding a way to continue in college?
If you are motivated to reach your college goal, good! Now look closely at your budget to determine what’s needed. If you can’t solve the budget shortfall by cutting back on “optional” expenses, then you need more dramatic changes. Are you paying a high rent because your apartment is spacious or near campus? Can you move a little farther away and get by temporarily in a smaller place, if the difference in rent makes a big difference in your overall finances? If you’re spending a lot on your car, can you sell it and get by with public transportation for a year or two? Play with the numbers for such items in your budget and see how you can cut expenses to stay in college without getting deeply in debt. If you worry you won’t be as happy if you change your lifestyle, remember that money problems are a key source of stress for many college students and that stress affects your happiness as well as how well you do in college. It’s worth the effort to work on your budget and prevent this stress.
If all else fails, see a financial aid counselor at your college. Don’t wait until you’re in real financial trouble before talking to someone who may be able to offer help.

Keep monitoring your spending habits and watch for things you’re spending money on without really thinking about it.
-
Credit cards.
Never use them if at all possible. They make it easy to spend too much or not see how much you’re spending. Save them for emergencies.
-
Easy access to cash.
Just put your card in an ATM and get some cash! It’s so easy to do, and an automatic habit for so many, that it’s easy to bust your budget with small amounts daily.
-
Temptations are everywhere.
Even when we’re careful, we’re often easily influenced by friends to go out or spend in other ways. Remember why you made your budget in the first place and keep your priorities in mind. The guilt you’ll feel tomorrow about spending a whole week’s food budget on one expensive dinner out probably isn’t worth the pleasure of it!
-
We buy things to feel good.
If that’s been a longtime habit for you, it will be hard to break. Often it’s better to find small things that make you feel good rather than trying to go without everything. Rewarding yourself with an ice cream treat for a week’s budgeting success won’t break your budget.
What If You Get in Financial Trouble?
People often don’t admit to themselves that they have a problem until it becomes unmanageable. We human beings are very good at rationalizing and making excuses to ourselves! Here are some warning signs of sliding into financial trouble:
-
For two or three months in a row, your budget is unbalanced because you’re spending more than you are bringing in.
-
You’ve begun using your savings for routine expenses you should be able to handle with your regular budget.
-
You’ve missed a deadline for a bill or are taking credit card cash advances or overdrawing your checking account.
-
You have a big balance on your credit card and have paid only the required minimum payment for the last two months.
-
You have nothing in the bank in case of an emergency need.

-
You’re trying to cut expenses by eliminating something important, such as dropping health insurance or not buying required textbooks.
If you are experiencing any of these warning signs, first acknowledge the problem. It’s not going to solve itself—you need to take active steps before it gets worse and affects your college career.
Second, if you just cannot budget your balance, admit that you need help. There’s no shame in that. Start with your college counselor or the financial aid office; if they can’t help you directly, they can refer you to someone who can. Take your budget and other financial records with you so that they can see what’s really involved. Remember that they’re there to help—their goal is to ensure you succeed in college.
Balance Your Checkbook!
Lots of people don’t balance their checkbook every month, thinking it’s just too much trouble. But it’s important to keep your checkbook balanced for several reasons:
-
Banks sometimes make errors, and you can’t catch one without checking your record against your monthly bank statement.
-
If you make a math error or forget to record a check or ATM withdrawal, you may have to pay overdraft fees.
-
If you balance your checkbook only every few months, it can take many hours to examine records and find a problem.
If you’re not sure how exactly to balance your checkbook, ask a teller at your bank or get instructions online. This takes only a few minutes each month and is well worth it to avoid the stress and lost hours caused by an inevitable problem.
Saving for the Future
If you’re having problems just getting by on your budget, it may seem pointless to even think about saving for the future. Still, if you can possibly put aside some money every month into a savings plan, it’s worth the effort:
-
An emergency or unexpected situation may occur suddenly. Having the savings to cope with it is much less stressful than having to find a loan or run up your credit cards.
-
Saving is a good habit to develop. Saving for the future will prepare you well for the increasing financial complexities of life after graduation.
-
You may need your savings to help launch your career after graduation. If you’re broke when you graduate, you may feel you have to take the first job that comes along, but with some savings you may have time to find the job that’s perfect for you.
-
You may change your mind about future plans. Maybe you now think that you’ll go to work at a good job right after graduation, so you’re not concerned about saving—but maybe in a couple years you’ll decide to go to graduate school, law school, or business school—or to start your own business, or to join a volunteer program. Your savings may allow you to pursue a new goal.
Start by saving in a savings account at your bank or credit union. You can have a certain amount transferred from your checking account every month into a savings account—that makes it easier and more routine. A savings account allows withdrawal anytime but pays lower interest than other accounts. Ask at your bank about money market accounts and certificates of deposit (CDs), which generally pay higher interest but have restrictions on minimum balances and withdrawals. Savings bonds are another option. All of these options are federally insured, so your money stays safe. Risky investments like the stock market are generally not appropriate for college students on a budget.
Key Takeaways
-
Financial success while in college depends on understanding and controlling your expenditures.
-
There are many ways you can spend less on optional expenses, and even essentials, and still have a full life and enjoy your college experience.
-
A detailed monthly budget that lists all income sources and expenditures makes it easier to track expenses and avoid sliding into financial trouble.
-
Spending too much can quickly lead to financial problems. If you see the signs that you’re starting to have money problems, take steps quickly to prevent trouble before it snowballs out of control.
-
While it may seem difficult just to make ends meet, make it a goal also to attempt to save something for future needs.
Checkpoint Exercises
-
List the top three optional expenditures you usually make every week.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
-
List three tips for spending less that you feel you will be able to use routinely to avoid running out of money while in college.
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
-
For each of the following statements, circle T for true or F for false:
References
Federal Student Aid, “Budget Calculator,” Federal Student Aid Direct Loans, www.ed.gov/offices/OSFAP/Dire...lc/budget.html (accessed July 13, 2010).


2 .
What prenatal diagnostic tests are performed in the first trimester?
3 .
What education would you give your patient who was considering prenatal screening and diagnostic testing?
4 .
What is the main role of the nurse in the second trimester screenings?
5 .
You are caring for a pregnant person who is at 26 weeks’ gestation. In reviewing the chart, you notice that the pregnant person completed the antibody titer and is Rh negative. Knowing this, what do you anticipate being ordered?
6 .
What second trimester screenings may be recommended and why?
7 .
The OB/GYN recommends that a patient who is 32 weeks pregnant perform fetal movement counts at home. The provider asks you, the nurse, to give the patient instructions on how to do this. How would you teach the patient to perform FMC?
8 .
What third trimester prenatal screenings might be recommended and why?


6.2.2: Other Applications
Consider how we might organize an epidemiological triangle for another infectious disease. We would need to learn the answers to several questions: What kind of pathogen is the agent? How does the disease get transmitted between humans? What type of environment is hospitable to the agent or increases the likelihood of transmission? What characteristics of the host make them more susceptible to disease? These factors help epidemiologists and policymakers develop policies, interventions, and harm-reduction strategies for different outbreaks.
Now consider how we might apply the epidemiological triangle to something other than an infectious disease. What about a disease caused by an environmental exposure such as radiation or lead? What about diseases caused by alcohol consumption, or cigarette smoke? Or what about traumatic injury or violence? Each of these could fill the role of the “agent”. And each of these epidemiological triangles would have different agent, environment and host factors.


2.7: Transition Metals and Coordination Chemistry (Exercises)
1. Write the electron configurations for each of the following elements:
- a. Sc
-
Let's start off by identifying where Scandium sits on the periodic table: row 4, group 3. This identification is the critical basis we need to write its electron configuration.
By looking at Scandium's atomic number, 21, it gives us both the number of protons and the number of electrons. At the end of writing its electron configuration, the electrons should add up to 21.
At row 4, group 3 Sc, is a transition metal; meaning that its electron configuration will include the D orbital.
Now, we can begin to assign the 21 electrons of Sc to orbitals. As you assign electrons to their orbitals, you move right across the periodic table.
Its first 2 electrons are in the 1s orbital which is denoted as
1s 2
where the "1" preceding the s denotes the fact that it is of row one, and it has an exponent of 2 because it fulfills the s orbital's maximum electron number. Now we have 21-2=19 more electrons to assign.
Its next 2 electrons are in the 2s orbital which is denoted as
2s 2
where the "2" preceding the s indicates that it is of row two, and it has an exponent of 2 because it fulfills the s orbital's maximum electron number. Now we have 19-2=17 more electrons to assign.
Its next 6 electrons are in the 2p orbital which is denoted as
2p 6
where the "2" preceding the p indicates that it is of row two, and it has an exponent of 6 because it fulfills the p orbital's maximum electron number. Now we have 17-6=11 more electrons to assign.
Its next 2 electrons are in the 3s orbital which is denoted as
3s 2
where the "3" preceding the s indicates that it is of row three, and it has an exponent of 2 because it fulfills the s orbital's maximum electron number. Now we have 11-2=9 more electrons to assign.
Its next 6 electrons are in the 3p orbital which is denoted as
3p 6
where the "3" preceding the p indicates that it is of row three, and it has an exponent of 6 because it fulfills the p orbital's maximum electron number. Now we have 9-6=3 more electrons to assign.
Its next 2 electrons are in the 4s orbital which is denoted as
4s 2
where the "4" preceding the s indicates that it is of row four, and it has an exponent of 2 because it fulfills the s orbital's maximum electron number. Now we have 3-2=1 more electron to assign.
Its last electron would be alone in the 3 d orbital which is denoted as
3d 1
where the "3" preceding the d indicates that, even though it is technically of row 4, by disregarding the first row of H and He, this is the third row and it has an exponent of 1 because there is only 1 electron to be placed in the d orbital. Now we have assigned all of the electrons to the appropriate orbitals and sub-orbitals, so that the final, entire electron configuration is written as:
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 1
This is the long-hand version of its electron configuration.
So for Sc, its short-hand version of its electron configuration would therefore be:
[Ar] 4s 2 3d 1
- b. Ti
-
Start off by identifying where Titanium sits on the periodic table: row 4, group 4, meaning it has 22 electrons total. Titanium is one element to the right of the previous problem's Sc, so we will basically use the same method except, in the end, there will be 2 electrons remaining, so therefore the final orbital will be denoted as:
3d 2
If needed, look above to the exact steps for how to do it in detail again; the long-hand electron configuration for Titanium will be:
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2
So for Ti, its short-hand version of its electron configuration would therefore be:
[Ar] 4s 2 3d 2
- c. Cr
-
c. Cr
Start off by identifying where Chromium sits on the periodic table: row 4, group 6, that means it has a total of 24 electrons. But first, Cr, along with Mo, Nb, Ru, Rh, Pd, Cu, Sg, Pt and Au, is a special case. You would think that since it has 24 electrons that its configuration would look like:
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 4
which is how we learned it earlier. However, this electron configuration is very unstable because of the fact that there are 4 electrons in its 3 d orbital. The most stable configurations are half-filled (d 5 ) and full orbitals (d 10 ), so the elements with electrons resulting in ending with the d 4 or d 9 are so unstable that we write its stable form instead, where an electron from the preceding s orbital will be moved to fill the d orbital, resulting in a stable orbital.
If needed, look above to the exact steps for how to do the beginning of the configuration in detail again. However we have to apple the new rule to attain stability so that the long-hand electron configuration for Chromium will be:
1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 3d 5
So for Cr, its short-hand version of its electron configuration would therefore be:
[Ar] 4s 1 3d 5
- d. Fe
-
Start off by identifying where Iron sits on the periodic table: row 4, group 8, meaning it has 26 electrons total. This is 5 elements to the right of the previous problem's Sc, so we will basically use the same method except, in the end, there will be 6 electrons remaining, so therefore the final orbital will be denoted as:
3d 6
If needed, look above to the exact steps for how to do it in detail again; the long-hand electron configuration for Iron will be:
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6
So for Fe, its short-hand version of its electron configuration would therefore be:
[Ar] 4s 2 3d 6
- e. Ru
-
Start off by identifying where Ruthenium sits on the periodic table: row 5, group 8, that means it has a total of 44 electrons. But first, as stated earlier, Ru, along with Cr, Mo, Nb, Rh, Pd, Cu, Sg, Pt and Au, is a special case. You would think that since it has 44 electrons that its configuration would look like:
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 6
which is how we learned it earlier. However, this electron configuration is very unstable because of the fact that, even though there are 4 paired electrons, there are also 4 electrons unpaired. This results in a very unstable configuration, so to restore stability, we have to use a configuration that has the most paired electrons, which would be to take an electron from the s orbital and place it in the d orbital to create:
5s 1 4d 7
If needed, look above to the exact steps for how to do the beginning of the configuration in detail again. However we have to apple the new rule to attain stability so that the long-hand electron configuration for Ru will be:
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 4d 7
So for Cr, its short-hand version of its electron configuration would therefore be:
[Kr] 5s 1 4d 7
2. Write the electron configurations for each of the following elements and its ions:
- a. \(Ti\)
-
Titanium has an atomic number of 22, meaning it has 22 electrons. The noble gas prior to Titanium is Argon. Looking at row 4 of the periodic table, Titanium still has 4 electrons to be placed in orbitals since Argon has 18 electrons that are already placed. The remaining electrons will fill the \(4s\) orbital and the remaining two electrons will go into the \(3d\) orbital. [Ar]4s 2 3d 2
- b. \(Ti^{+2}\)
-
This is an ion with a plus 2 charge, meaning 2 electrons have been removed. The electrons will be removed from the \(4s\) orbital and the 2 remaining electrons will be placed in the \(3d\) orbital. Like number 1, the prior noble gas is Argon. [Ar]3d 2
- c. \(Ti^{+3}\)
-
This is an ion with a plus 3 charge, meaning 3 electrons have been removed. The first 2 electrons will be removed from the \(4s\) orbital, and the third will be taken from the \(3d\) orbital, and the 1 remaining electron will be placed in the 3d orbital. Like number 1, the prior noble gas is Argon. [Ar]3d 1
- d. \(Ti^{+4}\)
-
This is an ion with a plus 4 charge, meaning 4 electrons have been removed. The first 2 electrons will be removed from the \(4s\) orbital and the second 2 will be removed from the \(3d\) orbital. This results in the ion having the same electron configuration as Argon. [Ar]
3. Write the electron configurations for each of the following elements and its 3+ ions:
- La
b. Sm
c. Lu
- Answer
- La: [Xe]6 s 2 5 d 1 , La 3 + : [Xe]; Sm: [Xe]6 s 2 4 f 6 , Sm 3 + : [Xe]4 f 5 ; Lu: [Xe]6 s 2 4 f 14 5 d 1 , Lu 3 + : [Xe]4 f 14
4. Indicate the coordination number for the central metal atom in each of the following coordination compounds:
a. [Pt(H 2 O) 2 Br 2 ]
- Answer
- a. The 2 aqua and the 2 bromo ligands form a total of 4 coordinate covalent bonds and as a result the coordination number is 4;
- b. The ammine, pyridine, chloro and bromo each form one coordinate covalent bond that gives a total of 4 and hence CN=4;
- c.
- e. Four aqua ligands and two chloro ligands form a total of 6 coordinate covalent bonds and a CN =6;
- f. Ethylenediamine is a bidentate ligand that forms two coordinate covalent bonds and along with two cyano ligands it forma a total of 6 bonds. hence has a CN=6
b. [Pt(NH 3 )(py)(Cl)(Br)] (py = pyridine, C 5 H 5 N)
- Answer
- b. The ammine, pyridine, chloro and bromo each form one coordinate covalent bond that gives a total of 4 and hence CN=4;
c. [Zn(NH 3 ) 2 Cl 2 ]
- Answer
- c.  [Zn(NH 3 )(py)(Cl)(Br)]
- Answer
- d.
e. [Ni(H 2 O) 4 Cl 2 ]
- Answer
- e. Four aqua ligands and two chloro ligands form a total of 6 coordinate covalent bonds and a CN =6;
f. [Fe(en) 2 (CN) 2 ] + (en = ethylenediamine, C 2 H 8 N 2 )
- Answer
- f. Ethylenediamine is a bidentate ligand that forms two coordinate covalent bonds and along with two cyano ligands it forma a total of 6 bonds. hence has a CN=6
5. Give the coordination numbers and write the formulas for each of the following, including all isomers where appropriate:
- tetrahydroxozincate(II) ion (tetrahedral)
- hexacyanopalladate(IV) ion
- dichloroaurate ion (note that aurum is Latin for "gold")
- diaminedichloroplatinum(II)
- potassium diaminetetrachlorochromate(III)
- hexaaminecobalt(III) hexacyanochromate(III)
- dibromobis(ethylenediamine) cobalt(III) nitrate
- Answer
- To determine coordination numbers we must count the total number of ligands bonded to the central metal and distinguish monodentate and polydentate ligands. To determine the formulas, we use the nomenclature rules and work backwards.
-
a. "tetrahydroxo" = 4 hydroxide ligands, since hydroxide is a monodentate ligand, we have a total of 4 bonds to the central metal
Coordination Number: 4
Since the charge on Zinc is 2+ which is given in the nomenclature by the roman numerals, we can calculate the total charge on the complex is 2-
Formula: [Zn(OH) 4 ] 2− -
b. "hexacyano" = 6 cyanide ligands, since cyanide is a monodentate ligand, we have a total of 6 bonds to the central metal
Coordination Number: 6
We review the basics of nomenclature and see that "hexa" = 6 and "cyano" = CN - . Since the charge on Pd is 4+ which is given in the nomenclature by the roman numerals, we can calculate the total charge on the complex is 2-
Formula: [Pd(CN) 6 ] 2− -
c. "dicholor" = 2 chloride ligands, since chloride is a monodentate ligand, we have a total of 2 bonds to the central metal
Coordination Number: 2
We review the basics of nomenclature and see that "di" = 2 and "chloro" = Cl - . Since the charge on Au is always 1+, we can calculate the total charge on the complex is 1-
Formula: [AuCl 2 ] − -
d. "diamine" = 2 ammonia ligands and "dichloro" = 2 chloride ligands, since both ammonia and chloride ligands are monodentant, we have a total of 4 bonds to the central metal
Coordination Number: 4 - e. 6, [Co(NH 3 ) 6 ][Cr(CN) 6 ];
- f. 6, [Co(en) 2 Br 2 ]NO 3
6. Give the coordination number for each metal ion in the following compounds:
- [Co(CO 3 ) 3 ] 3− (note that CO 3 2 − is bidentate in this complex)
- [Cu(NH 3 ) 4 ] 2+
- [Co(NH 3 ) 4 Br 2 ] 2 (SO 4 ) 3
- [Pt(NH 3 ) 4 ][PtCl 4 ]
- [Cr(en) 3 ](NO 3 ) 3
- [Pd(NH 3 ) 2 Br 2 ] (square planar)
- K 3 [Cu(Cl) 5 ]
- [Zn(NH 3 ) 2 Cl 2 ]
- Answer
- You can determine a compound's coordination number based on how many ligands are bound to the central atom.
- a. In this compound, Cobalt is the central atom, and it has 3 CO 3 2 - molecules attached to it. However, CO 3 2 - is a bidentate ligand, which means it binds to the central atom in two places rather than one. This means that the coordination number of [Co(CO 3 ) 3 ] 3- is 6. A coordination number of 6 means that the structure is most likely octahedral.
- b. In this compound, Copper is the central atom. 4 ammonia molecules are attached to it. This means the coordination number is 4, and the structure is likely tetrahedral.
- c. For this compound, we can ignore the (SO 4 ) 3 because it is not bound to the central atom. The central atom is cobalt, and it has 4 ammonia molecules and 2 bromine molecules bound to it. The coordination number is 6.
- d. There are two compounds here, indicated by the brackets. The central atom for both is platinum. One of them has 4 ammonia molecules attached, and the other has 4 chlorine atoms attached. Both complexes have a coordination number of 4.
- e. We can ignore (NO 3 ) 3 for this compound. The central atom is Chromium. There are 3 ethylenediamine molecules attached to the chromium. Ethylenediamine is a bidentate ligand, so the coordination number is 6.
- f. Palladium is the central atom. 2 ammonia molecules and 2 bromine atoms are bound to the palladium atom. The coordination number is 4.
- g. We can ignore the K 3 structure. Copper is the central atom, and there are 5 chlorine molecules attached to it. The coordination number is 5, so the structure is either trigonal bipyramidal or square pyramidal.
- h. In this compound, zinc is the central atom. There are 2 ammonia molecules and 2 chlorine atoms attached. This means that the coordination number is 4.
7. Sketch the structures of the following complexes. Indicate any cis , trans , and optical isomers.
- [Pt(H 2 O) 2 Br 2 ] (square planar)
- [Pt(NH 3 )(py)(Cl)(Br)] (square planar, py = pyridine, C 5 H 5 N)
- [Zn(NH 3 ) 3 Cl] + (tetrahedral)
- [Pt(NH 3 ) 3 Cl] + (square planar)
- [Ni(H 2 O) 4 Cl 2 ]
- [Co(C 2 O 4 ) 2 Cl 2 ] 3− (note that \(\ce{C2O4^2-}\) is the bidentate oxalate ion, \(\ce{−O2CCO2-}\))
- Hint
- Cis and trans are a type of geometric isomer, meaning there is a difference in the orientation in which the ligands are attached to the central metal. In cis, two of the same ligands are adjacent to one another and in trans, two of the same ligands are directly across from one another.
- Optical isomers → have the ability to rotate light, optical isomers are also chiral. Only chiral complexes have optical isomers
- Chiral → asymmetric, structure of its mirror image is not superimposable
- Enantiomers: chiral optical isomers (compound can have multiple enantiomers)
- Tetrahedral complex with 4 distinct ligands → always chiral
- For tetrahedral, if 2 ligands are the same, then it cannot be chiral, has a plane of symmetry
- Solutions:
- Answer
- a. \([Pt(H_2O)_2Br_2]\) (square planar)
- This complex has 2 kinds of ligands. The matching ligands can either be adjacent to each other and be cis, or they can be across from each other and be trans.
- b. \([Pt(NH_3)(py)(Cl)(Br)]\) (square planar, py = pyridine, \(C_5H_5N\))
- This complex has 4 different ligands. There is no plane of symmetry in any of the enantiomers, making the structures chiral and therefore has optical isomers.
- c. \([Zn(NH_3)_3Cl]^+\) (tetrahedral)
- There is a plane of symmetry from \(NH_3\) through \(Zn\) to the other \(NH_3\), therefore it is not chiral.
- d. \([Pt(NH_3)_3Cl]^+\) (square planar)
- There is a plane of symmetry from \(NH_3\) through \(Pt\) to the other \(NH_3\), therefore it is not chiral.
- e. \([Ni(H_2O)_2Cl_2]\)
- The \(Cl\) ligands can either be right next to each other, or directly across from one another allowing for both cis and trans geometries.
- f. \([Co(C_2O_4)_2Cl_2]^-3\) (note that \(C_2O_4^-2\) is the bidentate oxalate ion, \(^−O_2CCO_2^-\)
- There is a plane of symmetry from \(Cl\) through Co to the other \(Cl\) in a "trans" chlorine configuration, therefore it is not chiral in a chlorine "trans" configuration. However, there is no symmetry in the chlorine "cis" configuration, indicating multiple "cis" isomers.
8. Draw diagrams for any cis , trans , and optical isomers that could exist for the following (en is ethylenediamine):
- [Co(en) 2 (NO 2 )Cl] +
- [Co(en) 2 Cl 2 ] +
- [Pt(NH 3 ) 2 Cl 4 ]
- [Cr(en) 3 ] 3+
- [Pt(NH 3 ) 2 Cl 2 ]
- Hint
- We are instructed to draw all geometric isomers and optical isomers for the specified compound. Optical isomers exist when an isomer configuration is not superimposable on its mirror image. This means there are two distinct molecular shapes. Often a left and right hand are cited as an example; if you were to take your right hand and place it upon your left, you cannot make the major parts of your hand align on top of one another. The basic idea when deciding whether something is optically active is to look for a plane of symmetry--if you are able to bisect a compound in a manner that establishes symmetry, then the compound does not have an optical isomer.
- Cis isomers exist when there are 2 ligands of the same species placed at 90 degree angles from each other. Trans isomers exist when there are 2 ligands of the same species placed at 180 degree angles from each other.
- Problem 1
- Answer
- a. This compound is an octahedral molecule, so the six ligands (atoms in the complex that are not the central transition metal) are placed around the central atom at 90 degree angles. Two optical isomers exist for [Co(en) 2 (NO 2 )Cl] + . The second isomer is drawn by taking the mirror image of the first.
- b. This compound is also an octahedral molecule. Two cis (optical) isomers and one trans isomer exist for [Co(en) 2 Cl 2 ] + . The trans isomer can be drawn by placing the chlorine ligands in positions where they form a 180 degree angle with the central atom. The first cis isomer can be drawn by placing the chlorine ligands in positions where they form a 90 degree angle with the central atom. The second cis isomer can be found by mirroring the first cis isomer, like we did in a.
- c. This compound is also an octahedral molecule. One trans isomer and one cis isomer of [Pt(NH 3 ) 2 Cl 4 ] exist. The trans isomer can be drawn by placing the ammonia ligands in positions where they form a 180 degree angle with the central atom. The cis isomer can be drawn by placing the ammonia ligands in positions where they form a 90 degree angle with the central atom.
- d. This compound is also an octahedral molecule. Two optical isomers for [Cr(en) 3 ] 3+ exist. The second optical isomer can be drawn by taking the mirror image of the first optical isomer.
- e. This compound is a square planar complex, so the ligands are placed around the central atom in a plane, at 90 angles. A trans isomer and a cis isomer exist for the complex [Pt(NH 3 ) 2 Cl 2 ]. The trans isomer can be drawn by placing the ammonia ligands in positions where they form a 180 degree angle in the plane with the central atom. The cis isomer can be drawn by placing the ammonia ligands in positions where they form a 90 degree angle in the plane with the central atom.
9. Name each of the compounds or ions given in Exercise 6, including the oxidation state of the metal.
- Hint
- Rules to follow for coordination complexes
- 1. Cations are always named before the anions.
- 2. Ligands are named before the metal atom or ion.
- 3. Ligand names are modified with an ‐o added to the root name of an anion. For neutral ligands the name of the molecule is used, with the exception of OH2, NH3, CO and NO.
- 4. The prefixes mono‐, di‐, tri‐, tetra‐, penta‐, and hexa‐ are used to denote the number of simple ligands.
- 5. The prefixes bis‐, tris‐, tetrakis‐, etc., are used for more complicated ligands or ones that already contain di‐, tri‐, etc.
- 6. The oxidation state of the central metal ion is designated by a Roman numeral in parentheses.
- 7. When more than one type of ligand is present, they are named alphabetically. Prefixes do not affect the order.
- 8. If the complex ion has a negative charge, the suffix –ate is added to the name of the metal.
- 9. In the case of complex‐ion isomerism the names cis, trans, fac, or mer may precede the formula of the complex‐ion name to indicate the spatial arrangement of the ligands. Cis means the ligands occupy adjacent coordination positions, and trans means opposite positions just as they do for organic compounds. The complexity of octahedral complexes allows for two additional geometric isomers that are peculiar to coordination complexes. Fac means facial, or that the three like ligands occupy the vertices of one face of the octahedron. Mer means meridional, or that the three like ligands occupy the vertices of a triangle one side of which includes the central metal atom or ion.
- Answer
- a. tricarbonatocobaltate(III) ion;
- b. tetraaminecopper(II) ion;
- c. tetraaminedibromocobalt(III) sulfate;
- d. tetraamineplatinum(II) tetrachloroplatinate(II);
- e . tris- (ethylenediamine)chromium(III) nitrate;
- f. diaminedibromopalladium(II);
- g. potassium pentachlorocuprate(II);
- h. diaminedichlorozinc(II)
10. Name each of the compounds or ions given in Exercise 8.
Answer
- a. Chlorobis(ethylenediamine)nitrocobalt(III)
- b. Dichlorobis(Ethylenediamine)cobalt(III)
- c. Diamminetetrachloroplatinum(IV)
- d. Tris(ethylenediamine)cromium(III)
- e. Diamminedichloroplatinum(II)
11. Specify whether the following complexes have isomers.
- tetrahedral [Ni(CO) 2 (Cl) 2 ]
- trigonal bipyramidal [Mn(CO) 4 NO]
- [Pt(en) 2 Cl 2 ]Cl 2
- Answer
- a. none;
- b. none;
- c. The two Cl ligands can be cis or trans . When they are cis , there will also be an optical isomer.
12. Predict whether the carbonate ligand \(\ce{CO3^2-}\) will coordinate to a metal center as a monodentate, bidentate, or tridentate ligand.
- Answer
- CO 3 -2 will coordinate to a metal center as a monodentate ligand.
13. Draw the geometric, linkage, and ionization isomers for [CoCl 5 CN][CN].
- Hint
- Isomers are compounds with same formula but different atom arrangement. There are two subcategories: structural isomers , which are isomers that contain the same number of atoms of each kind but differ in which atoms are bonded to one another, and stereoisomers , isomers that have the same molecular formula and ligands, but differ in the arrangement of those ligands in 3D space.
- There are three subcategories under structural isomers: ionization isomers , which are isomers that are identical except for a ligand has exchanging places with an anion or neutral molecule that was originally outside the coordination complex; coordination isomers , isomers that have an interchange of some ligands from the cationic part to the anionic part; and linkage isomers , in two or more coordination compounds in which the donor atom of at least one of the ligands is different.
- There are also two main kinds of stereoisomers: geometric isomers , metal complexes that differ only in which ligands are adjacent to one another (cis) or directly across from one another (trans) in the coordination sphere of the metal, and optical isomers , which occurs when the mirror image of an object is non-superimposable on the original object.
- Some of the isomers look almost identical, but that is because the CN ligand can be attached by both (but not at the same time) the C or N.
- Answer
Spectroscopic and Magnetic Properties of Coordination Compounds
14. Determine the number of unpaired electrons expected for [Fe(NO 2 ) 6 ] 3− and for [FeF 6 ] 3− in terms of crystal field theory.
- Hint
- The crystal field theory is is a model that describes the breaking of degeneracies of electron orbital states, usually d or f orbitals, due to a static electric field produced by a surrounding charge distribution.
- The degenerate d-orbitals split into two levels, e\(_{g}\) and t\(_{2g}\), in the presence of ligands.
- The energy difference between the two levels is called the crystal-field splitting energy, \(\Delta_{\circ}\).
- After 1 electron each has been filled in the three t\(_{2g}\) orbitals, the filling of the fourth electron takes place either in the e\(_{g}\) orbital or in the t\(_{2g}\), where the electrons pair up. depending on whether the complex is high spin or low spin.
- If the \(\Delta_{\circ}\) value of a ligand is less than the pairing energy (P), then the electrons enter the e\(_{g}\) orbital, but if the \(\Delta_{\circ}\) value of a ligand is more than the pairing energy (P), then the electrons enter the t\(_{2g}\) orbital.
- when the is less than the pairing energy, the electrons prefer then e g orbitals because there is not enough energy to pair the electrons together. It will be high spin
- when the is more then the pairing energy, the electrons prefer the t 2g because there is enough energy to pair the electrons. It will be low spin.
- Step 1: Determine the oxidation state of the Fe
- For \([Fe(NO_{2}){_{6}}]^{3-}\) and \([FeF_{6}]^{3-}\), both \(NO_{2}\) and \(F_{6}\) have a charge of -1. Since there is 6 of them then that means the charge is -6 and in order for there to be an overall charge of -3, Fe has to have a +3 charge.
- Step 2: Determine type of ligand
- Based on the spectrochemical series we can see that \(NO_{2}^{-}\) is a stronger field ligand than F\(^{-}\), and therefore is a low spin complex because it has a high \(\Delta_{\circ}\) unlike F\(^{-}\) which is a high spin.
- Step 3: Draw the crystal field
- \([Fe(NO_{2}){_{6}}]^{3-}\)
- \([FeF_{6}]^{3-}\)
- There is 1 unpaired electron for \([Fe(NO_{2}){_{6}}]^{3-}\), and 5 for \([FeF_{6}]^{3-}\) based on the crystal field theory.
- Answer
- [Fe(NO 2 ) 6 ] 3− :1 electron
- [FeF 6 ] 3− :5 electrons
15. Draw the crystal field diagrams for [Fe(NO 2 ) 6 ] 4− and [FeF 6 ] 2− . State whether each complex is high spin or low spin, paramagnetic or diamagnetic, and compare Δ oct to P for each complex.
- Answer
16. Give the oxidation state of the metal, number of d electrons, and the number of unpaired electrons predicted for [Co(NH 3 ) 6 ]Cl 3 .
- Answer
- a. The ox state is 3+, there are 6 d electrons, there are no unpaired electrons
17. The solid anhydrous solid CoCl 2 is blue in color. Because it readily absorbs water from the air, it is used as a humidity indicator to monitor if equipment (such as a cell phone) has been exposed to excessive levels of moisture. Predict what product is formed by this reaction, and how many unpaired electrons this complex will have.
- Answer
- [Co(H 2 O) 6 ]Cl 2 with three unpaired electrons.
18. Is it possible for a complex of a metal in the transition series to have six unpaired electrons? Explain.
- Answer
- It is not possible for a metal in the transition series to have six unpaired electrons. This is because transition metals have a general electron configuration of (n-1)d 1-10 ns 1 -2 where n is the quantum number. The last electron will go into the d orbital which has 5 orbitals that can each contain 2 electrons, yielding 10 electrons total. According to Hund's Rule, electrons prefer to fill each orbital singly before they pair up. This is more energetically favorable. Since there are only 5 orbitals and due to Hund's Rule, the maximum number of unpaired electrons a transition metal can have is 5. Therefore, there cannot be a complex of a transition metal that has 6 unpaired electrons.
- For example, lets look at iron's electron configuration. Iron has an electron configuration of 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 . Now the most important orbital to look at is the d orbital which has 6 electrons in it, but there are only 4 unpaired electrons as you can see by this diagram:
- 3d: [↿⇂] [↿] [↿][↿][↿]
- Each [ ] represents an orbital within the d orbital. This diagram follows Hund's rule and shows why no transition metal can have 6 unpaired electrons.
19. How many unpaired electrons are present in each of the following?
- [CoF 6 ] 3− (high spin)
- [Mn(CN) 6 ] 3− (low spin)
- [Mn(CN) 6 ] 4− (low spin)
- [MnCl 6 ] 4− (high spin)
- [RhCl 6 ] 3− (low spin)
- Answer
- a. 4; b. 2; c. 1; d. 5; e. 0
20. Explain how the diphosphate ion, [O 3 P−O−PO 3 ] 4− , can function as a water softener that prevents the precipitation of Fe 2 + as an insoluble iron salt.
- Answer
- The diphosphate ion, [O 3 P−O−PO 3 ] 4− can function as a water softener keeping the iron in a water soluble form because of its more negative electrochemical potential than water's. This is similar to the way plating prevents metals from reacting with oxygen to corrode.
- Mineral deposits are formed by ionic reactions. The Fe 2 + will form an insoluble iron salt of iron(III) oxide-hydroxide when a salt of ferric iron hydrolyzes water. However, with the addition of [O 3 P−O−PO 3 ] 4− , the Fe 2 + cations are more attracted to the PO 3 group, forming a Fe(PO 3 ) complex.
- The excess minerals in this type of water is considered hard thus its name hard water.
21. For complexes of the same metal ion with no change in oxidation number, the stability increases as the number of electrons in the t 2 g orbitals increases. Which complex in each of the following pairs of complexes is more stable?
- [Fe(H 2 O) 6 ] 2+ or [Fe(CN) 6 ] 4−
- [Co(NH 3 ) 6 ] 3+ or [CoF 6 ] 3−
- [Mn(CN) 6 ] 4− or [MnCl 6 ] 4−
- Hint
- The Spectrochemical Series is as follows \[I^{-}<Br^{-}<SCN^{-}\approx Cl^{-}<F^{-}<OH^{-}<ONO^{-}<ox<H_{2}O<SCN^{-}<EDTA<NH_{3}<en<NO_{2}^{-}<CN\]
- The strong field ligands (on the right) are low spin which fills in more electrons in the t 2 g orbitals. The weak field ligands (on the left) are high spin so it can fill electrons in the t 2 g orbitals and e g orbitals. In conclusion, more electrons are filled up from the strong field ligands because the electrons don't move up to the e g orbitals.
- Answer
- a. [Fe(CN) 6 ] 4− ; b. [Co(NH 3 ) 6 ] 3+ ; c. [Mn(CN) 6 ] 4−
Q19.3.9
Trimethylphosphine, P(CH 3 ) 3 , can act as a ligand by donating the lone pair of electrons on the phosphorus atom. If trimethylphosphine is added to a solution of nickel(II) chloride in acetone, a blue compound that has a molecular mass of approximately 270 g and contains 21.5% Ni, 26.0% Cl, and 52.5% P(CH 3 ) 3 can be isolated. This blue compound does not have any isomeric forms. What are the geometry and molecular formula of the blue compound?
S19.3.9
1)Find the empirical formula. There is a total of 270 grams. To find out how many grams of each element/compound there are, multiply the percentage by the mass (270).
\[(270g)(0.215)=58.05gNi\]
\[(270g)(0.26)=70.2gCl\]
\[(270g)(0.525)=141.75gP(CH_3)_3\]
Now that we have the grams of each element/compound, we can convert them to moles by using their molar mass.
\[(58.055gNi)(\frac{1mol.}{58.69gNi})=0.989mol.Ni\]
\[(70.2gCl)(\frac{1mol.}{35.45gCl})=1.98mol.Cl\]
\[(141.75gP(CH_3)_3)(\frac{1mol.}{76.07gP(CH_3)_3})=1.86mol.P(CH_3)_3\]
Now that we have the moles of all elements/compounds, we can find the ratio of all them to each other. To do this, we take the element/compound with the least amount of moles and divide all element/compound moles by this amount. In this case, Ni has the least number of moles.
\[\frac{0.989mol.Ni}{0.989mol.Ni}=1\]
\[\frac{1.98mol.Cl}{0.989mol.Ni}=approx.2\]
\[\frac{1.86mol.P(CH_3)_3}{0.989mol.Ni}=approx.2\]
We now know the ratio of all element/compounds in the blue compound.
The empirical formula is: NiCl(P(CH 3 ) 3 ) 2
This formula shows us there are 4 ligands. There are 2 chlorine ligands and 2 trimethylphosphine ligands. This means that the blue compound has either a tetrahedral or square planar shape, where tetrahedral shapes are capable of different isomeric forms when all ligands are different (because if not, there is only 1 way for them to be arranged), and square planar shapes are capable of cis/trans forms. In the problem, it states this compound does not have any isomeric forms, therefore this has a tetrahedral shape.
A19.3.9
a) NiCl(P(CH 3 ) 3 ) 2
b) Tetrahedral
Q19.3.10
Would you expect the complex [Co(en) 3 ]Cl 3 to have any unpaired electrons? Any isomers?
S19.3.10
Assign oxidation states to each element. Cl- has a -1 oxidation state. En is neutral, so 0. The entire complex is also neutral, so in order to balance the charges out, Co must be +3 because there are 3 chlorides, which gives a -3 charge.
STEP 2:
Write the electron configuration for \(Co^{3+}\). \([Ar]3d^6\). There are 6 electrons.
STEP 3:
Check where en lies on the spectrochemical series. Does it have a strong field strength? It does, so these electrons will exist at the d-level with high splitting energy because the magnitude of the pairing energy is less than the crystal field splitting energy in the octahedral field.
You will the notice that there aren't any unpaired electrons when you draw the Crystal Field Theory (CFT) diagram.
This complex does not have any geometric isomers because cis-trans structures cannot be formed. The mirror image is nonsuperimpoasable, which means the enantiomers are chiral molecules; if the mirror image is placed on top on the original molecule, then they will never be perfectly aligned to give the same molecule.
A19.3.10
The complex does not have any unpaired electrons. The complex does not have any geometric isomers, but the mirror image is nonsuperimposable, so it has an optical isomer.
Q19.3.11
Would you expect the Mg 3 [Cr(CN) 6 ] 2 to be diamagnetic or paramagnetic? Explain your reasoning.
S19.3.11
The first step to determine the magnetism of the complex is to calculate the oxidation state of the transition metal. In this case, the transition metal is Cr.
Before doing so, we need to find charge of the of the complex ion [Cr(CN) 6 ] 2 given that the oxidation state of Mg 3 is 2+. Using the subscripts of the \(\displaystyle Mg^{2+}\) ion and the [Cr(CN) 6 ] 2 complex, we find that the oxidation state of [Cr(CN) 6 ] 2 , x, to be:
\(\displaystyle 3(+2)+2(x)=0\)
\(\displaystyle x=3\)
Now that we found the charge of the coordination complex, we are able to find the charge of the transition metal Cr given that the charge of CN is -1. Again, using the subscripts we find the oxidation state of Cr, y, to be:
\(\displaystyle y + 6(-1)=-3\)
\(\displaystyle y=3\)
Therefore, the oxidation state of the transition metal Cr is \(\displaystyle Cr^{3+}\)
Next, using the transition metal \(\displaystyle Cr^{3+}\) and the periodic table as reference, we can determine the electron configuration of \(\displaystyle Cr^{3+}\) to be \(\displaystyle [Ar]d^{3}\). This means that \(\displaystyle Cr^{3+}\) has 3 unpaired electrons in the 3d sublevel. Therefore, we find that since at least one electron is unpaired(in this case all 3 electrons are unpaired), Mg 3 [Cr(CN) 6 ] 2 is paramagnetic.
A19.3.11
a) Paramagnetic
Q19.3.12
Would you expect salts of the gold ion, Au + , to be colored? Explain.
S19.3.12
No. Colored ions have unpaired electrons in their outmost orbital . A partially filled d orbital, for example, can yield various colors. After completing the noble gas configuration, we see that Au + has a configuration of [Xe] 4f 14 5d 10 . Since Au + has a completely filled d sublevel , we are certain that any salts of the gold ion, Au + will be colorless.
*An example of a colored ion would be copper(II). Cu 2 + has an electron configuration of [Ar]3d 9 . It has one unpaired electron. Copper(II) appears blue.
A19.3.12
No. Au + has a complete 5 d sublevel.
Q19.3.13
[CuCl 4 ] 2− is green. [Cu(H 2 O) 6 ] 2+ is blue. Which absorbs higher-energy photons? Which is predicted to have a larger crystal field splitting?
S19.3.13
Although a color might appear a certain way, it actual absorbs a different color, opposite of it on the color wheel.
In this case;
[CuCl 4 ] 2- appears green but is opposite of red on the color wheel which is absorbed and is characterized by wavelengths 620-800 nanometers.
[Cu(H 2 O) 6 ] 2+ appears blue but is opposite of orange on the color wheel which is absorbed and is characterized by wavelengths 580-620 nanometers.
When determining which absorbs the higher energy photons, one must look at the complex itself. A higher energy indicates a high energy photon absorbed and a lower energy indicates a lower energy photon absorbed. How can we determine this? By looking at the complex and more specifically the ligand attached and its location in the spectrochemical series.
The ligands attached are Water and Chlorine and since Water is a stronger ligand than Chlorine according to the series, it also has larger energy, indicating a higher energy. This means that the complex [Cu(H 2 O) 6 ] 2+ absorbs a higher energy photon because of its a stronger ligand than chlorine.
Part 2 of this question also asks which complex is predicted to have a larger crystal field splitting. To determine this you also use the spectrochemical series and see which ligand is stronger. Since H 2 O is stronger than Cl - on the spectrochemical series, we can say [Cu(H 2 O) 6 ] 2+ has a higher crystal field splitting.
A19.3.13
a) [Cu(H 2 O) 6 ] 2+
b) [Cu(H 2 O) 6 ] 2+ has a higher crystal field splitting