1.
Sahara Williams

2. VSEPR Theory
Electron groups repel one another through coulombic forces.
The repulsion of between electron groups on interior atoms (central atoms) of a molecule determine the geometry of a molecule
Used when looking at 2 dimensional Lewis structures to determine what they would look like in 3 dimensions

3. Determining Geometry Electron groups want to have maximum separation
For molecules with one interior atom molecular geometry depends on
The number of surrounding electron groups
The number of bonding groups and lone pairs
There are 5 basic shapes of molecules
Linear geome6
Trigonal planar geometry
Tetrahedral geometry
Trigonal bipyramidal geometry
Octahedral geometry

4. How to represent molecular geometry on paper

5. Linear Geometry Two electron groups 180 degrees of separation
No lone pairs Y

6. Trigonal planar geometry
Three electron groups
120 degree bond angles
No lone pairs

7. Tetrahedral geometry Four electron groups 109.5 degree bond angles
Contains unshared pairs

8. Trigonal Bipyramidal geometry
Five electron groups
Equatorial bond (the three bonds on the Trigonal plane) angles 120 degrees , axial bond (the two bonds on either side of the plane) angles 90 degrees
Contains unshared pairs

9. Octahedral geometry Six electron groups Bond angles 90 degrees
Contains unshared pairs

10. Lone pairs
Electron geometry- the geometrical arrangement of electron groups
Molecular geometry- the geometrical arrangement of atoms
Lone pairs exert slightly greater repulsion than bonding electrons

11. Four electron groups with lone pairs
Electron geometry is tetrahedral
Molecular geometry is Trigonal pyramidal
Bond angles for 1 unshared pair is 107 degrees
Bond angles for 2 unshared pairs is degrees

12. Five electron groups with lone pairs
Electron geometry is Trigonal Bipyramidal
1 group of unshared electrons occupy the equatorial position
Two 90 degree interactions - seesaw
2 groups of unshared electrons occupy the Equatorial position
Two 90 degree interaction - t shaped
3 groups of unshared pairs occupy 3 Equatorial positions
Linear geometry

13. Six electron groups with lone pairs
Electron geometry is octahedral
1 unshared pair is square pyramidal
2 unshared pairs are square planar

14. Predicting geometries for larger molecules
Larger molecules have 2 or more interior atoms
Draw the Lewis structure of the given molecule
determine the geometry of each interior atom
Connect them from left to right.