Balance each of the subsequent oxidation-reduction reactions. For each of the reaction, demonstrate how electrons are gained and lost during the reaction.
i) Mg(s) + O2 (g) ----> MgO(s)
ii) Na(s) + S(s) ----> Na2 S(s)
iii) Al(s) + Sn(NO3)2 (aq) -----> Al(NO3)3 + Sn(s)
iv) Li(s) + Cl2 (g) ----> LiCl(s)