Question

Define molecules of elements and molecules of compounds along with a few examples.

Answer 1

(I) Molecules of elements ​: Molecules formed from same kind of atoms.
For example: $N_2$ , $O_3$ , $H_2$

(II) Molecules of compounds ​: Molecules formed from different kinds of atoms.
For example: $H_{2}O$ , $N{O}_2$ , $N{H}_3$