1. Chemistry Chapter 9 Notes #3

2. Representing Molecules Molecular Formula –Ex. CH 4 –Ex. H 2 O Structural/ Lewis Formula Ball & Stick Model Space Filling Model

3. Exceptions to the Octet Expanded Octet –Ex. PCl 5 –Due to a d e- Odd # valence e- Less than 8 e- The odd # and the less than 8 tend to bond with other molecules

4. Molecular Shape VSEPR Model –Valence shell electron pair repulsion model –Used to determine the shape, or geometry, of a molecule –The angle formed by any 2 terminal atoms and the central atom = bond angle –Pairs of electrons repel each other –Pairs are take up more space (they are only attracted to one nuclei)

5. Molecular Shape Common Shapes 1. Linear –No lone pairs of electrons –Atoms are at a 180 degree angle from each other

6. Molecular Shape Common Shapes 2. Trigonal Planar –No lone pairs on the central atom –3 shared pairs –Central atom has 3 terminal atoms attached’ –Bond angle = 120 degrees

7. Molecular Shape Common Shapes 3. Tetrahedral –No lone pairs on the central atom –Central atom has 4 terminal atoms attached –4 shared pair –Bond angle = 109.5 degrees

8. Molecular Shape Common Shapes 4. Bent –2 lone pairs –2 shared pair –Central atom has 2 terminal atoms attached –Bond angle = 105 degrees

9. Molecular Shape Common Shapes 5. Trigonal Pyramidal –1 lone pairs –Central atom has 3 terminal atoms attached’ –Bond angle = 107 degrees

10. Review Bent Trigonal Pyramidal