Question

Describe the properties of O, S, Se, Te and Po (group 16 elements) with reference to oxidation states.

Answer 1

1. All group 16 elements (O, S, Se, Te, Po) commonly show an oxidation state of −2 due to having six valence electrons and needing two to complete their octet.
2. Oxygen mainly shows −2 oxidation state but also +2 in OF₂ and −1 in peroxides. It cannot show higher positive states due to the absence of vacant d-orbitals.
3. Sulphur, selenium, and tellurium can exhibit +2, +4, and +6 oxidation states because they can use vacant d-orbitals for bonding.
4. Polonium shows the +4 oxidation state more stably than the +6 due to the inert pair effect.
5. The tendency to show −2 oxidation state decreases down the group from O to Po.

This reflects the progressive variation in oxidation states of group 16 elements caused by electronic structure and periodic trends.