Easy to understand Geometry of molecules.

1. 1

2. 2
VESPER THEORY
Presented By: Sagar Panhwar

3. VValencealence
SShellhell
EElectronlectron
PPairair
RRepulsionepulsion
TheoryTheory
Planar
triangular
Tetrahedral
Trigonal
pyramidal
Bent

4. VSEPR theory assumes that the shape of aVSEPR theory assumes that the shape of a
molecule is determined by themolecule is determined by the repulsionrepulsion ofof
electron pairs.electron pairs.
Molecular ShapeMolecular Shape

5. VSEPRVSEPR TheoryTheory
• Based on Electron Dot (Lewis structures)
• Theory predicts shapes of compounds
• abbreviated VSEPR
• VSEPR (pronounced “vesper”) stands for Valence
Shell Electron Pair Repulsion
• VSEPR predicts shapes based on electron pairs
repelling (in bonds or by themselves)
• Electrons around central nucleus repel each
other. So, structures have atoms
maximally spread out

6. VSEPR overviewVSEPR overview
• Each shape has a name
(you will have to know these)
• Names of Shapes:
• tetrahedral
• trigonal pyramidal
• Bent
• Linear
• trigonal planar

7. Triangular PlanarTetrahedral
Trigonal pyramidal
Linear
Bent or V
Models

8. methane, CHmethane, CH44
Bonds are all evenly spaced electronsBonds are all evenly spaced electrons
109.5°109.5°
TetrahedralTetrahedral

9. Less repulsion between the bonding pairs of electronsLess repulsion between the bonding pairs of electrons
.. ammoniaammonia
NHNH33
..
..
..
TrigonalTrigonal
PyramidalPyramidal

10. .. ..
..
109.5° (109.5° (109.5109.5°)°) 109.5° (109.5° (107107°)°) 109.5° (109.5° (104.5°)104.5°)
water, Hwater, H22OO

11. .. ..
..

12. Bent or VBent or V
2 unshared pairs of e’s at
top of O repel bonds and
force them to bend

13. Molecule Lewis Structure Number of
electron pairs
CH4
NH3
SHAPE
Tetrahedral
Trigonal
Pyramidal
4
4
(3 shared
1 lone pair)

14. Molecule Lewis Structure Number of
electron pairs
H2
O
CO2
SHAPE
Bent or V
4
(2 shared
2 lone pairs)
2
Linear

15. Molecule Lewis Structure Number of
electron pairs
BeCl2
BF3
SHAPE
2
3
Linear
Trigonal
Planar