1. WARM UP
How do you determine if a bond is ionic, polar covalent, or nonpolar?
How do you determine if an entire molecule is polar or nonpolar?
Draw a water molecule, indicating the + and – ends.

2. Intermolecular Forces

3. Video Demonstration

4. IMF Overview Force of attraction between + and – in separate molecules
Weaker than actual bonds
Coulomb’s Law
Larger charge or polarity, larger intermolecular force
Charles Coulomb

5. IMF Overview Polarizability
Ability of a nonpolar atom or molecule to become polar
Temporary and weak charge
Induced by an outside charge
More e- = higher polarizability = more charge

6. IMF Overview Studied by Johannes van der Waals Fritz London
Covalent forces (gases)
Fritz London
Dispersion forces

7. Ion-Ion
Ions in crystals
NaCl

8. Dipole-Dipole
Opposite ends of polar molecules

9. Hydrogen Bonds Very strong dipole-dipole Adjacent H and O/N/F attract
H bonded to O, N, or F
Adjacent H and O/N/F attract

10. Ion-Dipole
Ion and polar molecule
Salt water

11. Ion – Induced Dipole
Ion and nonpolar

12. Dipole – Induced Dipole
Polar and nonpolar
O2 in water

13. Dispersion / London (a.k.a. induced dipole – induced dipole)
Two nonpolars
CO2
Random e- movement creates temporary dipoles

14. WRAP UP
Explain the term polarizability, using an example.

15. WARM UP
List 5 different intermolecular forces, and write a 3-word description of each.

16. WRAP UP NH3 and NH3 CaF2 and H2O NaCl and H2 O2 and N2
Identify the intermolecular forces present in each of the following mixtures:
NH3 and NH3
CaF2 and H2O
NaCl and H2
O2 and N2