What is a difference between gas and liquid and solid on a molecular level?

The difference is in the movement in the molecules and their spatial arrangement.Molecules in gaseous states have the biggest freedom of movement, which means that they can move freely around. This is mainly due to the fact that intermolecular forces between the molecules are not as strong as in other states. In liquid state the molecules are much closer together due to stronger intermolecular forces and hence their movement is more limited comparing to the gaseous state. In solid state the movement of molecules is most restricted due to very strong intermolecular forces.