In physics, chemistry, and biology, intermolecular forces are forces that act between stable molecules or between functional groups of macromolecules. Intermolecular forces include momentary attractions between molecules, diatomic free elements, and individual atoms. These forces, most notably London Dispersion forces, dipole-dipole interactions and hydrogen bonding, are significantly weaker than either ionic or covalent bonding, but still have a noticeable chemical effect (see hydrogen bonding… (More on Intermolecular)