INTERMOLECULAR FORCES
Intermolecular Forces
• Forces of attraction and repulsion between
molecules.
• They are weak – if we say that a covalent bond
has a strength of 100 then intermolecular
forces would range from 0.001 to 15.
Dipole-Dipole
…A relatively strong force of attraction between
two polar molecules.
†Can also have ion-dipole forces between ions
and a polar molecule
Hydrogen Bonding
• …Is an exceptionally strong dipole-dipole force
• One of the three most electronegative
elements, F, O or N must be covalently bonded
to a hydrogen (such as HF, H2O, NH3 , CH3OH
and CH3NH2).
London Forces
• The only attractive force nonpolar molecules.
• …Basically the electrons in one atom are
slightly attracted to the nuclei (positive core)
of another atom.
• …The greater the number of electrons the
stronger the L.F.