1. Intermolecular Forces for 11U
Sec. 2.4 of text

2. Electronegativity, Bond Polarity and Polar Molecules
re-cap: (Gr. 10/11 rules)
electroneg. diff. > 1.7: ionic
between 0.4 and 1.7: polar (covalent)
<0.4: non-polar (purely or almost purely covalent)
but…
in CO2 the molecular geometry allows dipoles to cancel, therefore it is nonpolar

3. Nonpolar vs. Polar Molecules

4. Intramolecular vs Intermolecular

5. Intermolecular Forces or van der Waals forces or non-covalent forces
Ionic Compounds are not “molecules” -- It is debatable whether ionic interactions are to be seen as intermolecular forces, most consider them rather as a special kind of chemical bonding.
Molecules
Dipole-dipole interactions
Hydrogen Bonds (with N, O or F)
London (forces) who himself called it dispersion

6. From a real textbook (Brown, LeMay & Bursten; 1994)
Boiling points of the group 4A (bottom) and 6A (top) hydrides as a function of molecular wt.
Wasup with this?
If not for H-bonds, b.p of water = -100°C

7. Hydrogen Bonds & DNA

8. Intermolec. Ppty’s & Boiling Points
More electrons and greater M.W. allows for more London forces.