Magnesium oxide can be made by heating magnesium metal in

Solution: Here, we are going to determine the oxidation number of the indicated element in the given set of compounds. Step1: Oxidation number denotes the oxidation state of an element in a compound ascertained according to a set of rules. These rules are: 1. In elements, in the free or the uncombined state, each atom bears an oxidation number of zero. Evidently each atom in H2, O2, Cl2, O3, P4, S8, Na, Mg, Al has the oxidation number zero. 2. For ions composed of only one atom, the oxidation number is equal to the charge on the ion. In their compounds all alkali metals have oxidation number of +1, and all alkaline earth metals have an oxidation number of +2. Aluminium is regarded to have an oxidation number of +3 in all its compounds. 3. The oxidation number of oxygen in most compounds is –2. 4. The oxidation number of hydrogen is +1, except when it is bonded to metals in binary compounds (that is compounds containing two elements). 5. In all its compounds, fluorine has an oxidati