CHEMISTRY GUIDE

Topic 2.5 GROUP VII, THE HALOGENS Introduction to the Halogens Redox Properties of Halogens and Halide Ions Tests for Halide Ions Other Reactions and Uses of Chlorine and Its Compounds INTRODUCTION TO THE HALOGENS The halogens are the collective name given to the elements in group VII of the Periodic Table. There are five halogens; fluorine, chlorine, bromine, iodine and astatine. Astatine is very radioactive and cannot exist for more than a few microseconds before decaying. We will thus be concerned with the chemistry of fluorine, chlorine, bromine and iodine. All these elements are most commonly found in the -1 oxidation state, as X - ions. These are known as halide ions. i)          Structure Since each atom in this group has seven valence electrons, they tend to form diatomic molecules, eg F 2 , Cl 2 , Br 2 and I 2 ....