DISPERSION FORCES

                          DISPERSION FORCES :

• Weak forces.
• Form the temporary shifts in the density of electrons in electron clouds.
• When two non-polar molecules are in close contact, epecially when the collide, the electron cloud of one molecule repels the electron cloud of the other molecule.
• For a moment, the electron density around each nucleus is greater in one region of each cloud.
• Each molecule forms a temporary dipole.
• A weak dispersion force exists between oppositely charged regions of the dipoles when temporary dipoles are close together.
• Dispersion forces are the weakest intermolecular force due to the temporary nature of dipoles.
• It is the dominant force of attraction between identical no-polar molecules.