Intermolecular forces

• Intermolecular force of attraction


  An attractive force between neighboring molecules. It explains the behavior of substances. It determines the state of matter
• London dispersion forces


  • Also known as van der waals forces or dispersion forces.
  • Present in nonpolar molecules
  • The weakest among the forces
  • More massive molecules have stronger intermolecular forces
  • Present in all molecules
  • But the force is only on nonpolar molecules
• Dipole dipole forces


  - Present in polar molecules

  - This kind of force is stronger than london dispersion forces because polar molecules have a permanent uneven distribution of electrons

  - Positive end of one molecule attracts the negative end of another

  - Stronger than LDFs but weaker than hydrogen bonds
• Hydrogen bond


  • The strongest among the forces
  • A special kind of dipole dipole interaction
  • Happens when a hydrogen atom is bonded to fluorine, oxygen, or nitrogen