There are many types of molecules. These include:
1. Diatomic molecules- these molecules are composed of two atoms which may be similar or different. e.g H-H, H-Cl.
2. Heteronuclear Diatomic Molecules- consists of two atoms of the same element e.g O-O, H-H, N-N.
3. Biological molecules, e.g proteins
4. Homonuclear diatomic molecules- consists of two atoms of different elements, KCl