Wednesday, May 18, 2011

Exam Review Question #6

List the three main types of intermolecular forces and describe how each are formed Which intermolecular forces are the strongest and why?

1) Hydrogen bonds- strongest

-these bonds are polar molecules that form when a bond is made between H and F,N, or O -the large electronegativity difference in these bonds creates stronger dipoles

2) Dipole interactions- between polar molecules

-positive pole on one molecule is attracted to the negative pole of another -similar to ionic bonds but much weaker

3) London Dispersion forces- between non-polar molecules (weakest of all forces)

-step 1: Two molecules get close to each other

-step 2: The electrons in one molecule momentarily shift to form a dipole

-step 3: The momentary dipole in one molecule induces a dipole in another and they form an interaction