1. MOLECULAR GEOMETRY Bonding Unit

2. VSEPR VSEPR V alence S hell E lectron P air R epulsion theory.V alence S hell E lectron P air R epulsion theory. Most important factor in determining geometry is relative repulsion between electron pairs.Most important factor in determining geometry is relative repulsion between electron pairs. Molecule adopts the shape that minimizes the electron pair repulsions. MOLECULAR GEOMETRY

3. Some Common Geometries Linear Trigonal Planar Tetrahedral

4. VSEPR charts Use the Lewis structure to determine the geometry of the moleculeUse the Lewis structure to determine the geometry of the molecule Electron arrangement establishes the bond anglesElectron arrangement establishes the bond angles Molecule takes the shape of that portion of the electron arrangementMolecule takes the shape of that portion of the electron arrangement Charts look at the CENTRAL atom for all data!Charts look at the CENTRAL atom for all data!

6. 1.Two pairs of electron on a central atom in a molecule are always placed 180 o apart (linear). 2.Three pairs of electrons on a central atom in a molecule are always placed 120 o apart on the same plane as the central atom (trigonal Planar). 3.Four pairs of electrons on a central atom in a molecule are always placed 109.5 o apart (tetrahedral).

7. 4.When every pair of electrons on the central atom is shared with another atom, the molecular structure has the same name as the arrangement of the electron pairs. Number of PairsName of Arrangement 2Linear 3Trigonal Planar 4tetrahedral

8. 5.When one or more of the electron pairs around a central atom are lone pairs, the name for the molecular structure is different from the arrangement of electron pairs.

9. Structure Determination by VSEPR Structure Determination by VSEPR Water, H 2 O The electron pair geometry is TETRAHEDRAL The molecular geometry is BENT. 2 bond pairs 2 lone pairs

14. Determining polarity of a molecule based on the symmetry of the molecule.