VALENCE SHELL ELECTRON PAIR REPULSION THEORY Planar triangular

VALENCE SHELL ELECTRON PAIR REPULSION THEORY Planar triangular Tetrahedral Trigonal bipyramidal Octahedral

Essential Question • How is VSEPR Theory used to determine molecular geometry?

What is VSEPR Theory? • Valence Shell Electron Pair Repulsion Theory • Predicts molecular geometry (shape) • Only works for: • Covalent compounds & polyatomic ions • Compounds with central atom

Shape Depends On: • e- on central atom only • # of lone pairs • # of bonded atoms • Single, double, & triple bonds have the same effect (count as one bond) Atoms bonded Lone pair of electrons 2 bonded atoms, no lone pairs: linear Double bonds still count as one bonded atom

Steps to Determine Shape 1. Draw Lewis Dot Structure 2. Count # of lone pairs on central atom 3. Count # of bonded atoms on central atom 4. Determine shape using the VSEPR Shape Chart

5 Types of Shapes • The shape of a molecule can be categorized into 5 general shapes. • 1. Linear • 2. Trigonal Planar • 3. Tetrahedral • 4. Trigonal Bipyramidal • 5. Octahedral • The geometrical shape is the arrangement of the atoms around a central atom based on the number of atoms, and the amount of lone pairs, which contribute to the overall shape.

• To represent a 3 -D structure on a two dimensional surface, we use solid lines, dashed lines, and wedges, as seen below. Line= in the plane of the board Wedge= coming out of the board Dashes= going into the board