Transcript VSEPR

VSEPR THEORY
Valence Shell Electron Pair Repulsion theory.
States that in a small molecule, the pairs of
valence electrons are arranged as far apart
from each other as possible.
So far we have dealt with structural formulas
which only show the types of atoms, bonds
and lone pairs of electrons. They do not
show the shape of the molecule.
VSEPR – Valence Shell Electron Pair
Repulsion
X+E
Overall Structure
Forms
2
Linear
AX2
3
4
5
6
Trigonal Planar
AX3, AX2E
Tetrahedral
AX4, AX3E, AX2E2
Trigonal bipyramidal
AX5, AX4E, AX3E2, AX2E3
Octahedral
AX6, AX5E, AX4E2
A = central atom
X = atoms bonded to A
E = nonbonding electron pairs on A
Linear
AX2
CO2
LINEAR – two atoms bonded to the
central atom, no lone pairs of
electrons on the central atom.
The angle is 180 degrees and it
has “sp” hybridization.
TRIGONAL PLANAR EPG
• A trigonal planar molecule has 3
negative charge centers.
• It has angles of 120 degrees and “sp2”
hybridization.
Trigonal Planar
AX3
AX2E
BF3
SnCl2
TETRAHEDRAL EPG
• A tetrahedral molecule has four negative
charge centers.
• It has angles of 109.5 degrees and “sp3”
hybridization.
Tetrahedral
AX4
CCl4
AX3E
PCl3
AX2E2
Cl2O
Trigonal Bi-pyramidal
AX5
PCl5
AX4E
SF4
AX3E2
ClF3
AX2E3
I3-
Octahedral
AX6
SF6
AX5E
BrF5
AX4E2
ICl4-
Yikes
Feelin Good
Naming Ionic & Covalent
Lewis Dot and VSEPR
Empirical & Molecular Formulas