IM FORCES Notes:
- IM Forces – Intermolecular Forces
o Forces of attraction that exist between covalent molecules
o Weaker than both covalent bonds and ionic bonds
- Types of IM Forces:
o Van der Waals
 Dipole-Dipole Interactions
 Attraction between two polar
molecules.
 The ‘partially +’ end of one
molecule is attracted to the
‘partially -‘ end of another.
 London Dispersion
 ** WEAKEST attractions that exist
 Caused by movement of e More e- = stronger dispersion force.
o Plays a role in phases of matter
 Cl  gas (few e-)
 Br  liquid (more e-)
 I  solid (even more e-)
o Hydrogen Bonding
 Strongest of IM Forces – only
5% strength of covalent bond
 Attraction between the H of one
molecule and a very EN atom
(O, N, F, Cl) of another
molecule.
- MP/BP increase with strength of IM Forces
- Strength of all chemical attractions:
Ionic >> Nonpolar Covalent > Polar Covalent > H-Bond > Dipole >Dispersion
**intramolecular force
** intermolecular force