Why does magnesium from `Mg^(2+)` and not `Mg^(+)`?

Why does magnesium form Mg^(2+) and not Mg^(+) ?

Why MgO exist as Mg^(2+)O^(2-) not as Mg^(o+)O^(ɵ) whereas the formation of Mg^(2+) from Mg requires more energy than formation of Mg^(o+) and formation of O^(ɵ) from O is exothermic whereas the formation of O^(2-) is endothermic .

Why MgO exist as Mg^(2+)O^(2-) not as Mg^(o+)O^(ɵ) whereas the formation of Mg^(2+) from Mg requires more energy than formation of Mg^(o+) and formation of O^(ɵ) from O is exothermic whereas the formation of O^(2-) is endothermic .

1g of magnesium vapor absorbs 50 kJ of light enegry. Find the percentage of Mg^(+)(g) and Mg^(2+)(g) in the vapor if Delta_(i)H_(1) = 738kJ mol^(-1) and Delta_(i)H_(2) = 1450kJmol^(-1) . Strategy: Find the number of moles of Mg atoms present in 1g of Mg vapor. Find the moles of Mg^(+) and Mg^(2+) formed by absorbing enegry. Use the following ratio of calculate the percentage of Mg^(+)(g) : %Mg^(+)(g) = (n_(Mg^(+(g))))/(n_(Mg^((g))))xx100% Finally, % Mg^(2+) = 100% - % Mg^(+)(g)