VSEPR Theory
Valence Shell Electron Pair Repulsion
VSEPR Theory
0 Predicts the molecular shape of a bonded molecule…covalent
0 Electrons around the central atom arrange themselves as far
apart from each other as possible
0 Unshared pairs of electrons (lone pairs) on the central atom
repel the most
0 So only look at what is connected to the central atom
Linear
0 2 atoms attached to center atom
0 0 unshared pairs (lone pairs)
0 Bond angle = 180o
0 Ex. : BeF2
Trigonal Planar
0 3 atoms attached to center atom
0 0 lone pairs
0 Bond angle = 120o
0 Ex. : BF3
Tetrahedral
0 4 atoms attached to center atom
0 0 lone pairs
0 Bond angle = 109.5o
0 Ex. : CH4
Bent
0 2 atoms attached to center atom
0 2 lone pairs
0 Bond angle = 104.5o
0 Ex. : H2O
Trigonal Pyramidal
0 3 atoms attached to center atom
0 1 lone pair
0 Bond angle = 107o
0 Ex. : NH3