London dispersion force

Definition

London dispersion forces are weak intermolecular forces arising from temporary dipoles induced in atoms or molecules. They are present in all molecular interactions but are the only type of intermolecular force in nonpolar compounds.

5 Must Know Facts For Your Next Test

1. London dispersion forces increase with the size and mass of interacting particles.
2. These forces arise due to fluctuations in electron distribution within atoms and molecules.
3. They are generally weaker than other types of intermolecular forces such as hydrogen bonds and dipole-dipole interactions.
4. London dispersion forces contribute to the boiling points and melting points of substances, especially nonpolar compounds.
5. The strength of these forces is directly proportional to the polarizability of the molecule.

Review Questions

• What causes London dispersion forces?
• How do London dispersion forces affect boiling points in nonpolar substances?
• Why are London dispersion forces significant despite being weak?

Related terms

Dipole-Dipole Interactions: Intermolecular forces that occur between two polar molecules due to their permanent dipoles.

Hydrogen Bonding: A strong type of dipole-dipole interaction occurring between a hydrogen atom bonded to a highly electronegative atom (like N, O, or F) and another electronegative atom.

Polarizability: The ability of an electron cloud to be distorted, contributing to the strength of London dispersion forces.