Intermolecular Bonds and London Dispersion Forces
Intermolecular bonds occur between separate molecules and are weaker than the bonds within molecules. These Van der Waals forces come in three main types, with increasing strength: London Dispersion forces, Permanent dipole-Permanent dipole interactions, and Hydrogen bonding.
London Dispersion forces are the weakest type but exist between all atoms and molecules. They explain why even noble gases and molecular elements can condense into liquids and solids at low temperatures. These forces arise from temporary uneven distributions of electrons, creating momentary δ+ and δ- regions that attract neighboring molecules.
The strength of London Dispersion forces increases with molecular size. Larger atoms and molecules have more electrons, which can create stronger temporary dipoles and therefore stronger attractions between molecules.
Remember this: London Dispersion forces are universal – they occur between all molecules regardless of structure, unlike other intermolecular forces which require specific molecular features.
