Question

Oxygen gas is
O
O2
O3
H2O

Answer 1

O2

Step-by-step explanation:

The element is O, because the periodic table isn't describing molecules, it's describing atoms. The molecule is O2 because it takes 2 Oxygen atoms to make a molecule of oxygen.

Hope this helped : D

Answer 2

Oxygen gas is a dioxide ( a bond of two oxygen atoms).

It would be O2