Question

Atmospheric oxygen is denoted by what symbol?

Answer 1

`O_2(g)`

Explanation:

Oxygen as a gas is made up of molecules that each are built from two atoms of the element oxygen, that is denoted by `O`.

There is another form of oxygen, known as ozone `O_3`, that has three oxygen atoms per molecule. Though highly poisonous, it is an essential part of the upper atmosphere (it stops dangerous UV rays).