Molecular Geometry

2-D and 3-D• Lewis Structures explain the two dimensional

structure of molecules• In order to model the actual structure of a

molecule we need a model that is three dimensional

VSEPR

• Valence Shell Electron Pair Repulsion• Basically, the paired electrons in the covalent

bonds of a molecule exert a repulsive force on each other.

• Given the number of bonded pairs, and the number of lone pairs, we can predict the 3-D shape of a molecule

Linear

• Form: AX or AX2

• One or Two Bonded Pairs• Zero Lone Pairs• Bond Angle = 180°• Hybridization: sp

Trigonal Planar

• Form: AX3

• Three Bonded Pairs• Zero Lone Pairs• Bond Angle = 120°• Hybridization: sp2

Tetrahedral• Form: AX4

• Four Bonded Pairs

• Zero Lone Pairs

• Bond Angle = 109.5°

• Hybridization: sp3

Trigonal Pyramidal• Form: AX3E

• Three Bonded Pairs

• One Lone Pair• Bond Angle =

107°• Hybridization:

sp3

Bent• Form: AX2E2

• Two Bonded Pairs

• Two Lone Pairs

• Bond Angle = 104.5°

• Hybridization: sp3