Define atomicity. Give an example of each of monoatomic, diatomic, triatomic, and polyatomic molecules.

Atomicity: The number of atoms present in an element is called the atomicity of element.

Monoatomic: $Au,Ag,Fe$

Diatomic: $H_2,O_2,C{l}_2$

Triatomic: $O_3,S{O}_2$

Polyatomic: $H_{2}S{O}_4,CaC{O}_3$