Period 1 element lithium and fluorine (appearing twice), or left floating above the other elements and not assigned to any group in the periodic table. Helium is almost always placed above neon (which is in the p-block) in the periodic table as a noble gas, although it is occasionally placed above beryllium due to their similar electron configuration. Hydrogen (H) is the chemical element with atomic number 1. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H. With an atomic mass of 1.00794 amu, hydrogen is the lightest element. Hydrogen is
Element-reactant-product table reaction equation is not balanced, it needs coefficients to show equality. Here is an example with the separation of natural gas from hydrochloric acid using magnesium.<br> Mg + HCl = MgCl + H <br>Here is the element-reaction-product table:<br> From this table we see that the number of hydrogen and chlorine atoms on the product's side are twice the number of atoms on the reactant's side. Therefore, we add the coefficient "2" in front of the HCl on the products side, to get our equation to look like this:<br> Mg + 2HCl = MgCl + H<br> and our table looks like