Determining the Shape of a Molecule
The best way to determine the architecture of a molecule is to:
1. Determine what the central atom is.
2. Draw the Lewis structure of the molecule.
3. Determine the number of bonding pairs and lone pairs around
the central atom.
4. Refer to the following chart and determine the shape of the
molecule.
VSEPR CHART
A = central atom X = bonding pair E = lone
pair
# of
Electron
Pairs |
# of
Lone
Pairs |
VSEPR
notation |
Name |
Diagram |
| 2 |
0 |
AX2 |
Linear |
|
| 2 |
2 |
AX2E2 |
Bent |
|
| 2 |
3 |
AX2E3 |
Linear |
|
| 3 |
0 |
AX3 |
Planar triangular |
|
| 3 |
1 |
AX3E |
Trigonal pyramidal |
|
| 3 |
2 |
AX3E2 |
T-shaped |
|
| 4 |
0 |
AX4 |
Tetrahedral |
|
| 4 |
1 |
AX4E |
See-saw |
|
| 4 |
2 |
AX4E2 |
Square planar |
|
| 5 |
0 |
AX5 |
Trigonal bipyramidal |
|
| 5 |
1 |
AX5E |
Square pyramidal |
|
| 6 |
0 |
AX6 |
Octahedral |
 |
|
