Oxygen gas is always written as #O_2# in chemical equations. What term is used to describe the "2" in the formula?

1 Answer
Dec 20, 2015

The 2 in the formula #"O"_2"# is a subscript.

Explanation:

The formula for a molecule of oxygen gas is #"O"_2"#. It is a diatomic element, meaning it is composed of two atoms of oxygen, covalently bonded. The subscript 2 means that 2 atoms of oxygen are in one molecule of #"O"_2"#.