# How many atoms of oxygen are there on each side of the chemical equation 2Mg + O_2 -> 2MgO?

Feb 7, 2016

There are two on each side.

#### Explanation:

The expression

$2 M g + {O}_{2} \to 2 M g O$

Means

Two atoms of magnesium, plus one oxygen molecule (consisting of two atoms of oxygen) react to become two particles of magnesium oxide, each of which contains an oxygen.

Since the ${O}_{2}$ molecule has two oxygens, and two $M g O$'s each have one oxygen, there are two oxygens on each side.