As a group, halogens exhibit highly variable physical properties. Halogens range from solid (I2) to liquid (Br2) to gaseous (F2 and Cl2) at room temperature. The chemical properties are more uniform. The halogens have very high electronegativities.Fluorine has the highest electronegativity of all elements.alogens range from solid (I2) to liquid (Br2) to gaseous (F2 and Cl2) at room temperature. The chemical properties are more uniform. The halogens have very high electronegativities. Fluorine has the highest electronegativity of all elements.
A gene can exist in many different forms, calledalleles. For example, letâs say that there is one gene which determines the color of your hair. That one gene may have many forms, or alleles: black hair, brown hair, auburn hair, red hair, blond hair, etc. You inherit one allele for each gene from your mother and one from your father. Each of the two alleles you inherit for a gene each may be strong (dominant) or weak (recessive).
Hair color is a matter of chemistry! The first safe commercial hair color was created in 1909 by French chemist Eugene Schuller, using the chemical paraphenylenediamine. Hair coloring is very popular today, with over 75% of women coloring their hair and a growing percentage of men following suit. How does hair color work? It's the result of a series of chemical reactions between the molecules in hair, pigments, as well as peroxide and ammonia if present. What is Hair?