Question

Why do sulphur and other heavier elements of group 16 exhibit higher oxidation states?

Answer 1

1. Sulphur and heavier group 16 elements have vacant d-orbitals in their valence shells.
2. These vacant d-orbitals allow them to expand their octet and form more bonds beyond the common −2 oxidation state.
3. In the ground state, they show +2 oxidation state with two unpaired electrons.
4. By exciting electrons to d-orbitals, they form four bonds (+4 state) and six bonds (+6 state).
5. Oxygen lacks d-orbitals, so it mostly shows −2 or +2 states but not higher states.

Hence, sulphur and heavier elements show higher oxidation states (+4 and +6) due to d-orbital participation, which oxygen cannot do.