Answer:
2 Mg(s) + O2(g) → 2 MgO(s)
As magnesium (Mg) has a valency of +2, and oxygen (O) has a valency of -2, the ratio would be 1:1, and magnesium oxide would be represented as MgO. It is insoluble in water, hence it has the subscript as a solid, represented by (s). In order to use up the diatomic oxygen (O2), there needs to be two moles of magnesium (2Mg) on the reactant side. This would produce 2 moles of MgO on the product side.
Explanation:
