The elements that make up the group of halogens in row seven of the Periodic Table are Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At). Solids in this family consist of Iodine and Astatine, gasses are Fluorine and Chlorine, and Bromine is a liquid. Join us as we go through the history and uses of these various elements. All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1. The term halogen means "salt-former" and compounds containing halogens are called "salts".
General Trends in Halogen Chemistry
There are several patterns in the chemistry of the halogens.
1. Neither double nor triple bonds are needed to explain the chemistry of the halogens.
2. The chemistry of fluorine is simplified by the fact it is the most electronegative element in the periodic table and by the fact that it has no d orbitals in its valence shell, so it can't expand its valence shell.
3. Chlorine, bromine, and iodine have valence shell d orbitals and can expand their valence shells to hold as many as 14 valence electrons.
4. The chemistry of the halogens is dominated by oxidation-reduction reactions
THE GASES... Fluorine and Chlorine
THE SOLIDS... Iodine and Astatine
& THE LIQUID... Bromine