Class Notes 

Chapter 9:  Molecular Geometry



Under Construction

Valence Shell Electron Repulsion (VSEPR)
Dipole Moment
Hybrid Orbitals

Valence Shell Electron Repulsion 

"The best arrangement for a given number of electron pairs is the one that minimizes the repulsions among them"

Bonding Electron Pairs

Non-Bonding Electron Pairs

Counting Electron Pairs Around the Central Atom

  This number is obtained by adding the number of bonding and non-bonding electron pairs in the Lewis Structure

Electron-Pair Geometry

 Based on the number of electron pairs around the central atom

 Ideal Bond Angles

 Molecular Geometry

  It is the same as the electron-pair geometry only if all the electron pairs are equivalent,  otherwise the molecular geometry is a distorted electron pair geometry.
"  Distortions occur because of non-equivalent electron pairs."

Dipole Moment 

Based on the polarity of individual polar bonds and the molecular geometry a molecular polarity can be reasoned.

Hybrid Orbitals 

Valence Bond Theory

Atomic orbital set  -->  hybrid orbital set

Hybrid Geometry

Sigma Bonds

Pi Bonds

  They are found in multiple bonds