Answer
Anions are always larger and atomic radii increasing going down groups in the periodic table, so from increasing radii it goes: O, S, $O^{2-}$, $S^{2-}$
Work Step by Step
Anions are always larger and atomic radii increasing going down groups in the periodic table, so from increasing radii it goes: O, S, $O^{2-}$, $S^{2-}$
