What are some examples of intermolecular forces?
Most common ones are ionic, covalent, Van der Waal's and metallic bonding.
Ionic bonding exist where there is a transfer of electrons between elements. The forces of attraction must be huge enough so that the electron can be transferred from one atom of an element to another. For example, sodium chloride,
Covalent bonding exist when there is a sharing of electrons. The forces of attraction is not strong enough to pull the electrons away from the original atom, hence they share the electrons. An example would be ammonia,
Van der Waal's forces exist between molecules. This occurs when there is an electrostatic attraction between temporary dipoles and induced dipoles.
Metallic bonding occurs between metallic elements. The bonds hold the atoms together to ensure they do not just fly around.