Question

Oxygen gas is always written as O2 in chemical equations. What term is used to describe the "2" in the formula?

Answer 1

$\bold{OXYGEN}$

◼Oxygen is an element which lies in period 2 and group 16 of modern periodic table. So,

▶Electronic configuration = 2 ,6

▶Valency = -2.

✳Valency is the number od electrons needed to be stable like nearest noble gas.

◼Which means to be stable like nearest noble gas neon oxygen needs two electrons .So two oxygen atoms reacts and and shared there two electrons each with double covalent bond and both becomes stable like neon and there are four lone pairs.

✳Lone pairs are the one which don't takes part in the formation of a compound.

◼So ,in an oxygen compound there are two oxygen atoms which are present so two represent them it is written as

$\huge \boxed{O_2}$

where two represents the two oxygen atom.

Answer 2

Answer:

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 $O_2$.