Intermolecular

• Van der Waals forces occur when a temporary dipole in one atom introduces a tempoarary dipole in the opposite direction in a neighbouring atom causing the two atoms to be attracted to one another
• larger molecules have stronger van der waals forces than smaller molecules
• van der waals forces occur between every atom and molecule
• in molecules with permanent dipoles, dipole-dipole forces occur due to the weak electrostatic attraction between the delta positive and delta negative charges
• hydrogen bonding occurs when hydrogen is covalently bonded to fluorine, nitrogen or oxygen
• in hydrogen bonding, the bond is so polarised and the hydrogen has such a high charge density that it can form weak bonds with lone pairs on other oxygen, fluorine and nitrogen atoms
• intermolecular forces weakest to strongest

  • van der waals
  • dipole-dipole
  • hydrogen bonding