Question

how and why are atoms of oxygen always written as O2​

Answer 1

Answer:

So there are two reasons to write it as O2: 1. O2 is almost always the form of oxygen in a reaction, and 2. One needs to specify the form to describe how it will react. Other elements that usually exist as diatomic molecules are written as the dimer for the same reasons.

Answer 2

beacouse the oxygen is form by 2 scientifically