Question

how to take out the atomicity of oxygen

Answer 1

we know the no.of atom present in an element is known as its atomicity.Since oxygen contains 2 atoms so its atomicity is2.

Answer 2

Atomicity is nothing but the number of atoms in a molecule of Oxygen.In this case, oxygen molecule, or O₂, is the small number below the symbol or , atoms. Thus atomicity of a substance is the m=number of atoms present in it. eg: Atomicity of Ozone is 3, as the subscript is  O₃.