Valence Shell Electron Pair Repulsion Theory VSEPR Valence Shell Electron Pair Repulsion Theory “Atomium Building”, Andre Waterkeyn (architect), 1958

VSEPR Theory Atoms and lone pairs in molecules arrange themselves to minimize repulsion.

Make a Table Geom. Name # of bonded atoms to central atom Ball and Stick Model # of bonded atoms to central atom # of lone pairs on central atom Electron Domain Geometry Bond Angles Ex. Dot. Struct

Linear 2 180o GeomName Model # of bonded atoms # of lone pairs Bond Angles Ex. Dot. Struct See next slide 2 180o BeH2 Linear

Trigonal Planer 3 120o GeomName Model # of bonded atoms # of lone pairs Bond Angles Ex. Dot. Struct See next slide Trigonal Planer 3 120o BH3

Tetrahedral 4 GeomName Model # of bonded atoms # of lone pairs Bond Angles Ex. Dot. Struct See next slide 4 CH4 Tetra-hedral 109.5o

Trigonal Pyramidal 3 1 107o GeomName Model # of bonded atoms # of lone pairs Bond Angles Ex. Dot. Struct See next slide Trigonal Pyramidal 3 1 107o NH3

Bent 2 2 GeomName Model # of bonded atoms # of lone pairs Bond Angles Ex. Dot. Struct See next slide 2 2 H2O Bent 104.5o

Trigonal Bipyramidal 5 GeomName Model # of bonded atoms # of lone pairs Bond Angles Ex. Dot. Struct See next slide Trigonal Bipyra-midal 120o and 90o 5 PCl5

Octahedral 6 90o GeomName Model # of bonded atoms # of lone pairs Bond Angles Ex. Dot. Struct See next slide Octa-hedral 6 90o SF6