Question

Which of the follwing gas is diatomic?

Answer 1

Atomicity of an element is a measure of total number of atoms present in a molecule.
In Carbon dioxide ($C{O}_2$) Total number of atoms are 3 hence it is triatomic
In Hydrogen sulphide ($H_{2}S$) Total number of atoms are 3 hence it is also triatomic
Argon is an inert gas molecule it is mono atomic
In Oxygen ($O_2$) Total number of atoms are 2 hence it is diatomic.