Intermolecular Bonds:

Types of Bonds:

1. Intramolecular bonds = within a molecule (*think intramural)
    - Ionic + Covalent

2. Intermolecular bonds = between molecules (*think international)
    - The stronger the intermolecular bonds the higher the BP or MP
    - 2 Types: Vander Waals bonds & Hydrogen bonds

Vander Waals Bonds:

• Based on electron distribution
• 2 Categories: 

1. Dipole - Dipole bonds 

• if a molec. is Polar, the + end of one molec will be attracted to the - end of another molec. 

     2.  London Dispersion Forces (LDF)

• present in all molecs
• creates the weakest bonds 
• if a substance is non-polar Dipole - Dipole forces don't exist 
• electrons are free to move around & will randomly be grouped on one side of the molec. 
• Creates a temporary dipole and can cause a weak bond to form
• the more e- in the molec. the stronger the LDF will be

EX//

- NH3 (10e) VS. C2H8 (18e)
  polar                  non-polar

- NH3 has the stronger bond because of it's Dipole-Dipole bond.  C2H8 is non-polar thus it's bond is LDF making it's bond weaker than NH3.

Hydrogen Bonding:

• if hydrogen bonded to certain elements (F, O, & N) the bond is highly polar 
• this forms a very strong intermolecular bond.  

EX//

- H2O (10e) VS. CH4 (10e)
  Polar                 Polar

- They are both Polar and both have the same amount of e- but H2O wins for the highest boiling point due to its Hydrogen bond.

A very helpful Video... :)