Question

in the atmosphere,oxygen is available as O2 but not as O

Answer 1

In atmosphere oxegen is used as o2 because in atmosphere only gas is present that's why we have written o2

Answer 2

Hey mate here is your answer:-

The reason is that O is unstable in nature and it want to be stable so it share the electron to be stable.

Hope it helps you
Now plzz plzz mark my answer as BRAINLIEST