Question

in the reaction mg(s)+sn²⁺(aq) → sn(s) + mg²⁺(aq) as written: mg gets reduced, sn²⁺ gets oxidized both mg and sn²⁺ gets oxidized mg gets oxidized, sn²⁺ gets reduced the oxidation number of magnesium changed from +2 to 0.

Explanation:

Oxidation is loss of electrons and increase in oxidation number. Reduction is gain of electrons and decrease in oxidation number. In the reaction, Mg goes from 0 oxidation state to +2 (loses electrons, gets oxidized). $Sn^{2+}$ goes from +2 to 0 (gains electrons, gets reduced).

Answer:

Mg gets oxidized, $Sn^{2+}$ gets reduced