1. An attractive intermolecular force resulting from the tendency of polar molecules to align themselves such that the positive end of one molecule is near the negative end of another.
Diplole- Dipole
Van der Waals forces
The weak attractive forces between molecules or atoms resulting from the small, instantaneous dipoles that occur because of the varying positions of the electrons about the nuclei of atoms.
London Dispersion Forces
A weak to moderate attractive force that exists between hydrogen atoms covalently bonded to very electronegative atoms, particularly F, O, or N and the lone pair of electrons of another electronegative atom in another molecule
Hydrogen Bonding

2. P4O10, Cl2, AgCl, I2 Br2, Ne, HCl, N2 Ar, Kr, Xe, Ne
Circle the one with the lowest boiling point.
P4O10, Cl2, AgCl, I2
Circle the one with the highest intermolecular bond strength
Br2, Ne, HCl, N2
Circle the one with the highest boiling point.
Ar, Kr, Xe, Ne
Rank boiling points 1-5 (with 5 being the highest)
BaCl2, H2, CO, HF, Ne
HF, HCl, HBr, HI
Rank bond strengths 1-4 (with 4 being the highest)

3. Net force inward on the surface particles!
(Evidence of attractive forces at work!)
Surface Tension: A resistance in liquids to create new surfaces
…due to an imbalance of forces on particles on the surfaces of liquids

4. energy used to overcome attractive forces DHv
Heating Curve for a Typical Liquid
energy used to overcome attractive forces
DHv
Heat of vaporization
Temperature →
B.P.
L→ G L
clusters→ random
Time