Name the following :

A triatomic molecule

Atomicity

Atomicity of a molecule is the number of atoms present in a molecule of an element.

Monoatomic molecule means the molecule has just 1 atom in its molecule, diatomic means it has 2 molecules, triatomic means it has 3 atoms and so on.

Answer:

A triatomic molecule is ozone (${\mathrm{O}}_3$). The molecule of ozone has three atoms of oxygen in it.