1. Valence Shell Electron Pair Repulsion Theory
Planar triangular
Valence Shell Electron Pair Repulsion Theory
Tetrahedral
Trigonal pyramidal
Bent

2. In VSEPR, electrons in the valence shell repel each other
In VSEPR, electrons in the valence shell repel each other. This means that bonded atoms are as far apart as possible.
The positions of the atoms in a
molecule determine molecular shape.
Molecular shape
is important
because it can
determine the biological activity of molecules.

3. Hydrocodone (Vicodin) Codeine
In fact, changing one atom on a molecule can cause a huge change in the molecule’s properties. While both codeine and hydrocodone are pain killers, codeine can cause hallucinations in some patients. Notice the small difference in molecular structure between the two molecules.
Hydrocodone
(Vicodin)
Codeine

4. VSEPR overview Names of Shapes: tetrahedral trigonal pyramidal Bent
Each shape has a name
(you will have to know these)
Names of Shapes:
tetrahedral
trigonal pyramidal
Bent
Linear
trigonal planar

5. Practice.

6. .. ..
water, H2O
109.5° (109.5°)
109.5° (107°)
109.5° (104.5°)

7. .. ..

8. Bent or V
2 unshared pairs of e’s at top of O repel bonds and force them to bend