INTERMOLECULAR (IM) FORCES
*without them, all matter would be gases*

intermolecular forces:  forces of attraction between molecules

4 TYPES OF IM FORCES (in order from strongest to weakest)

1.    HYDROGEN "BONDING"
        * occurs between molecules that have hydrogen & nitrogen, hydrogen & oxygen, and
           hydrogen & fluorine
        * accounts for the unusually high boiling point of NH3, H2O, and HF

2.    DIPOLE-DIPOLE FORCES
        * occurs between polar molecules (dipoles)
        * the slightly positive end of one polar molecule is attracted to the slightly negative end
           of another polar molecule

3.    DIPOLE-INDUCED DIPOLE FORCES
        * occurs between a polar molecule (dipole) and a nonpolar molecule or between a polar
           molecule and a noble gas
        * the slightly positive end of a polar molecule temporarily attracts the electrons from a
           nonpolar molecule or noble gas

4.    LONDON DISPERSION FORCES
        * occurs between all molecules
        * only force that acts between nonpolar molecules and noble gases
        * moving electrons (in electron cloud of an atom) temporarily attract the electrons from
           another atom

** COVALENT BONDING IS STRONGER THAN ANY OF THESE IM FORCES.  **

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