The elements of Group 16 exhibit a number of oxidation states (Above Table).
The stability of -2 oxidation state decreases down the group.
Polonium hardly shows –2 oxidation state.
Since electronegativity of oxygen is very high, it shows only negative oxidation state as –2 except in the case of OF2 where its oxidation state is + 2.
Other elements of the group exhibit + 2, + 4, + 6 oxidation states but + 4 and + 6 are more common. Sulphur, selenium and tellurium usually show + 4 oxidation state in their compounds with oxygen and + 6 with fluorine.
The stability of + 6 oxidation state decreases down the group and stability of + 4 oxidation state increase (inert pair effect).
Bonding in +4 and +6 oxidation states are primarily covalent.