Presentation on theme: "VSEPR T HEORY Valence Shell Electron Pair Repulsion."— Presentation transcript:
VSEPR T HEORY Valence Shell Electron Pair Repulsion
VSEPR T HEORY 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
6 T YPES OF M OLECULES WITH NO U NSHARED P AIRS OF E LECTRONS
L INEAR 2 atoms attached to central atom 0 unshared pairs (lone pairs) Bond angle = 180 o Type: AB 2 Ex. : BeF 2
3 EXCEPTIONS TO THE OCTET RULE Molecules with an odd number of electrons Molecules with atoms near the boundary between metals and nonmetals will tend to have less than an octet on the central atom. (i.e. B, Be, Al, Ga) Molecules with a central atom with electrons in the 3 rd period and beyond will sometimes have more than an octet on the central atom, up to 12, called an extended or expanded octet.