The O2 Lewis structure shows two oxygen atoms bonded in the same way to each other. It's perfectly symmetric.

Generally, small symmetric molecules are nonpolar. The O2 Lewis structure indicates that the O2 molecule is perfectly symmetric. Therefore, O2 is a nonpolar substance.

O2 Lewis Structure Setup

It's easiest to think in terms of dots to make the O2 Lewis structure.

Oxygen needs to bond twice, shown as the lone dots on the left and right sides of the oxygen atoms in the below diagram. There are also two pairs of dots, representing four more electrons, that won't bond.

Think of connecting the lone dots to form bonds between each O atom. Each O atom needs to bond twice. So the pair of O atoms form two bonds with each other.

The two bonds appear as the two parallel lines between the O atoms. This is called a double bond. Each bond is a pair of electrons, one from each connected O atom. So the double bond, the two parallel lines, represents a total of 4 electrons.

Each O is surrounded by four dots and two sticks or lines, representing another 4 electrons in the O2 double bond. So each O is surrounded by 8 total valence electrons, giving it an octet and making it stable.