Question

With suitable explanations, give a brief account of the oxidation states exhibited by halogens.

Answer 1

1. Fluorine only exhibits −1 oxidation state, as it is the most electronegative and cannot show positive states.
2. Other halogens (Cl, Br, and I) exhibit oxidation states of −1, +1, +3, +5, and +7.
3. The common −1 state arises by gaining or sharing one electron to complete their valence shell.
4. Higher positive oxidation states occur due to excitation of electrons to vacant d-orbitals in heavier halogens.
5. Chlorine and bromine can also show +4 and +6 states in oxides and oxoacids.
6. Iodine shows slight metallic character and can form positive ions like I⁺ and I³⁺ under special conditions.

Thus, halogens mainly show −1 state, but heavier ones can also exhibit multiple positive oxidation states depending on the compound and excitation of electrons.