Question

Why does the tendency of group 16 elements to exist in −2 oxidation state decrease on moving down the group?

Answer 1

1. Group 16 elements have the electronic configuration ns² np⁴, needing 2 electrons to complete their octet and show −2 oxidation state.
2. Oxygen is highly electronegative and readily gains 2 electrons, making −2 state common.
3. Moving down the group, atomic size increases and electronegativity decreases.
4. Lower electronegativity reduces the tendency to gain electrons and form −2 ions.
5. Heavier elements (like Po) prefer positive oxidation states and rarely show −2 state.

Thus, the tendency to exist in the −2 oxidation state decreases down the group.