Lots of people get confused when they are discussing something about oxygen. Unfortunately those who are not related to the basic science, they don't understand the difference between oxygen and oxygen gas.
Oxygen is very reactive so it is not possible in the normal circumstances for the oxygen atom to stay in atomic shape, that is; oxygen atom O.
So oxygen reacts with another oxygen atom and makes oxygen gas. Which means O + O -------> O2
So whenever we're talking about oxygen gas, we will represent it by O2.
Oxygen is very reactive so it is not possible in the normal circumstances for the oxygen atom to stay in atomic shape, that is; oxygen atom O.
So oxygen reacts with another oxygen atom and makes oxygen gas. Which means O + O -------> O2
So whenever we're talking about oxygen gas, we will represent it by O2.