VSEPR THEORY
Chemistry Joke Q: How did the molecular spy introduce himself? A: My name is Bond… Covalent Bond.
VSEPR THEORY Valence Shell Electron Pair Repulsion
VSPER Theory Definition: Because electrons repel, molecular shape adjusts so the valence-electron pairs are as far……………..apart as possible.
Molecular Shape The number of atoms bonded to the central atom The shape of a molecule is determined by 2 factors: The number of atoms bonded to the central atom Double and triple bonds don’t change the general shape. The number of unshared pairs of electrons on the central atom Unshared pairs of electrons on other atoms in the compound don’t affect the shape.
We’ll Study 7 of the Shapes Linear Bent Trigonal Planar Trigonal Pyramidal Tetrahedral Trigonal Bipyramidal Octahedral
F C O Linear 2 atoms bonded to the central atom 0 lone pairs on the central atom All 2-atom molecules are considered linear. F C O
O H Bent 2 atoms bonded to the central atom 1 or 2 lone pairs on the central atom Notice that the Lewis structure does NOT have to show the bent shape. O H
H C O Trigonal Planar 3 atoms bonded to the central atom 0 lone pairs on the central atom Since there are no lone pairs on the central atom, the compound is flat. C H O
N H Trigonal Pyramidal 3 atoms bonded to the central atom 1 lone pair on the central atom The lone pair on the central atom pushes down on the other 3 atoms causing a pyramidal shape. N H
H C Tetrahedral 4 atoms bonded to the central atom 0 lone pairs on central atom C H
Trigonal Bipyramidal 5 atoms bonded to the central atom An extended octet Possible for p-group elements from 3rd or later periods 0 lone pairs on central atom
Octahedral 6 atoms bonded to the central atom Also an extended octet 0 lone pairs on central atom
Lone Pairs on Center Atom Summary Lone Pairs on Center Atom Atoms Bonded to Center Shape Linear 2 0 Bent 2 1 or 2 Trigonal Planar 3 0 Trigonal Pyramidal 3 1 Tetrahedral 4 0 Trigonal Bipyramidal 5 0 Octahedral 6 0
Chemistry Joke Have you heard any good jokes about sodium? Na!