What is the difference between diatomic and poly-atomic molecules? Site some examples.

Their difference lies in the prefix used before each root word, atom. The diatomic molecules are composed only of 2 atoms such as that of the diatomic elements: H2, O2, N2, Cl2, etc. On the other hand, polyatomic molecules are made up of three or mole atoms such as NH4+, H2SO4, etc.