• 1/4 to 1/6 of a covalent bond's strength 

• Form of ionic bond
• Strongest when aligned linearly
• 15-70kJ/mole
• in water, avg 3.5 bonds per molecule 

The more hydrogen bonds, the higher the boiling point.  Makes sense, since there are more bonds to break 

• Dipole-dipole interactions
• AKA london forces, dispersion forces
• Polar molecules = permanent dipole 

Temperature causes atoms to oscillate a little bit, electron cloud shifts a little bit in the atom.  So that causes a slight positive/slight negative charge on the atom.

• Not dipole, non polar
• Weaker than polar
• True for ALL molecules (even electronlically stable ones) 

        q1q2
F = ---------
      4piE0r^2

Where E0 = 8.85x10^-12

Two oppositely charged atoms should collide and BOOM form a glorious reaction
- BUT there's also repulsive force (Pauli exclusion principle), which increases as r decreases

U = Negative integral of the F(r) 

• Negative U = attractive
• Negative F = attractive  

Use general "6-12" potential, and look up the A and B constants for the two atoms.  Then use:
U = -A/r^6 + B/r^12
Force function is simply the derivative of that

Such that the electron forms a range of energies at bond distances.

Vs conductance and resistance