Compare and contrast intermolecular forces and describe intramolecular forces. intramolecular forces exist in non-polar molecules only; this makes them weak. intermolecular forces exist in both polar and non-polar molecules. intramolecular forces occur between particles; intermolecular forces hold particles together. intermolecular forces are include dispersion forces, and dipole-dipole, while intramolecular forces include hydrogen bonding. intermolecular forces occur between particles; intramolecular forces hold particles together.