1. Forces of Attraction Lecture

2. Intramolecular forces
Forces between atoms within a molecule
3 types:
Ionic
Cations and anions
Covalent
Positive nuclei and shared electrons
Metallic
Metal cations and mobile electrons
Occurs in pure metals (Fe)

3. Intermolecular forces
Forces between molecules
Dispersion
Dipolar
Hydrogen bonds

4. Dispersion Weakest intermolecular force
All molecules/compounds have this force between them
Caused by temporary shifts of electrons in the electron cloud
Only force between identical nonpolar molecules
The more electrons an atom has the stronger the dispersion force
F2 gas and Cl2 are gases at room temperature
Br2= liquid and I2= solid

5. Dipolar Force between two polar molecules
Caused by attraction between oppositely charged regions of the two polar molecules
Example: HCl

6. Hydrogen bond Special dipolar attraction
Attraction occurs between molecules containing H bonded to a small, electronegative atom (N, O or F only) with at least one lone pair of electrons