Question

How do you write the chemical formula for magnesium oxide?

Answer 1

Hint: The chemical formula of calcium magnesium oxide can be written by using the concept of the valency of the atom which is the capacity of any substance to gain/lose the electron. Valency of Mg is +2 and that of the O is -2. Now, you can easily write the chemical formula.

Complete step by step answer:
Magnesium oxide is an inorganic compound and it consists of the elements magnesium and oxygen.
We can find the formula of the magnesium oxide by using their valency i.e., on the basis of their tendency to lose or gain the electrons to complete their octet or to acquire stable electronic configuration of the nearest noble gas.
Magnesium atoms can lose a maximum of 2 electrons from its valence shell to attain the nearest noble gas configuration and thus exhibit +2 oxidation state in most of their compounds and so, its valency is +2. On the other hand, oxygen has a tendency to gain two electrons and thus exhibits -2 oxidation state in their compounds and so, its valency is 2.
So, the chemical formula of magnesium oxide is:

Mg	O
2	2
1	1

On cross multiplication, 1 with Mg and 1 with O, the chemical formula of the magnesium oxide turns out to be: $MgO$.

Note: When magnesium is made to react with oxygen it results in the formation of the magnesium oxide. The balanced chemical reaction of the magnesium oxide is as;
$2Mg+O_2\to 2MgO$