Inter-molecular force:
These are the force that helps in holding two covalent molecules together. It may be with forces of attraction or can be repulsion. E.g. atom or ions, ion induced dipole forces. It can be better understood by forces of attraction between the molecules of water. Here the intermolecular force helps in holding the hydrogen atom and oxygen atom of single water molecule. They are of four types, first one is
Ionic bond> hydrogen bond> dipole-dipole interaction > dispersion force.