VSEPRTheory.ppt
- 1. VSEPR Theory Valence Shell Electron Pair Repulsion
- 2. VSEPR Theory • Predicts the molecular shape of a bonded molecule • Electrons around the central atom arrange themselves as far apart from each other as possible • Unshared pairs of electrons (lone pairs) on the central atom repel the most • So only look at what is connected to the central atom
- 3. These are for molecules with only paired electrons around the central atom.
- 4. Linear • 2 atoms attached to center atom • 0 unshared pairs (lone pairs) • Bond angle = 180o • Type: AB2 • Ex. : BeF2
- 5. Trigonal Planar • 3 atoms attached to center atom • 0 lone pairs • Bond angle = 120o • Type: AB3 • Ex. : AlF3
- 6. Tetrahedral • 4 atoms attached to center atom • 0 lone pairs • Bond angle = 109.5o • Type: AB4 • Ex. : CH4
- 7. Trigonal Bipyramidal • 5 atoms attached to center atom • 0 lone pairs • Bond angle = – equatorial -> 120o – axial -> 90o • Type: AB5 • Ex. : PF5
- 8. Octahedral • 6 atoms attached to center atom • 0 lone pairs • Bond angle = 90o • Type: AB6 • Ex. : SF6
- 9. These are for molecules with both paired and unshared (lone) pairs of electrons around the central atom.
- 10. Bent • 2 atoms attached to center atom • 2 lone pairs • Bond angle = 104.5o • Type: AB2E2 • Ex. : H2O
- 11. Trigonal Pyramidal • 3 atoms attached to center atom • 1 lone pair • Bond angle = 107o • Type: AB3E • Ex. : NH3