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Intermolecular Forces

Intermolecular forces are forces between separate molecules. Compared to intramolecular forces, intermolecular forces are weaker but important in properties such as melting and boiling points, vapor pressure, solubility, and surface tension. Video by Professor Dave.

Intermolecular Forces

Intermolecular forces can occur between molecules. They influence whether a substance is a solid, liquid, or gas. Solids generally have strong intermolecular forces.

Intermolecular forces between neutral molecules are called van der Waals forces. This includes:

Dispersion Forces (London Forces) are attractions due to temporary/instantaneous dipoles.
Dipole-Dipole Attractions are attraction between polar covalent molecules. This includes Hydrogen Bonding (in molecules with F-H, O-H, and N-H intramolecular bonds).

More Help and Practice

Polar and Non-Polar Molecules (video)
Textbooks: ChemLibre, OpenStax, CK12

Note: The term intramolecular refers to the attraction between atoms chemically bonded in an individual molecule.