Question

Taking the example of chlorine, show that all halogens (except fluorine) can exhibit +l, +3, +5 and +7 oxidation states.

Answer 1

1. Chlorine and other halogens (except fluorine) can show multiple oxidation states due to the presence of vacant d-orbitals in their valence shells.
2. They can excite their ns and np electrons to these d-orbitals, allowing unpaired electrons to participate in bonding.
3. This leads to positive oxidation states of +1, +3, +5, and +7, as seen in chlorine compounds like Cl₂O (+1), ClO₂ (+4, related), \[\ce{ClO^-_3}\] (+5), and \[\ce{ClO^-_4}\] (+7).
4. Fluorine lacks vacant d-orbitals and is highly electronegative, so it only exhibits −1 oxidation state.

Hence, all halogens except fluorine can show +1, +3, +5, and +7 oxidation states due to their ability to expand the octet using d-orbitals.