1. Molecular Structure VSEPR Model

2. VSEPR Valence Shell Electron Pair Repulsion The structure around a given atom is determined principally by minimizing electron-pair repulsions Non-bonding and bonding electrons pairs will be as far apart as possible

3. Examples CO 2 BF 3 CH 4

4. Effect of Unshared Electron Pairs The ideal tetrahedral angle is 109.5° Lone (unshared) electron pairs require more room than bonding pairs They have greater repulsive forces Tend to compress the angles between bonding pairs Lone pairs do not cause distortion when bond angles are 120° or greater

5. Multiple Bonds Multiple bonds count as one effective electron pair When a molecule exhibits resonance, ANY of the resonance structures can be used to predict the molecular structure using the VSEPR model

6. No Single Central Atom Apply the principal of distancing shared and unshared electron pairs Look at real 3D models to develop predictive skills

7. VSEPR Models For non-ionic compounds – works in most cases