London Dispersion Forces

London Dispersion:  London dispersion forces result from instantaneous nonpermanent dipoles created by random electron motion.  London dispersion forces
are present in all molecules and are directly proportional to molecular size.

• are very weak forces of attraction between molecules resulting from:

1. momentary dipoles occurring due to uneven electron distributions in neighbouring molecules as they approach one another
2. the weak residual attraction of the nuclei in one molecule for the electrons in a neighbouring molecule.The more electrons that are present in the molecule, the stronger the dispersion forces will be.

• Dispersion forces are the only type of intermolecular force operating between non-polar molecules, for example, dispersion forces operate between hydrogen (H₂) molecules, chlorine (Cl₂) molecules, carbon dioxide (CO₂) molecules, dinitrogen tetroxide (N₂O₄) molecules and methane (CH₄) molecules.