Chapter 9

MoCu

VSEPR Theory Electron pairs around a central atom arrange themselves so that they can be as far apart as possible from each other.

• • Polarity When two atoms bond, a dipole moment occurs. If both atoms are of even size and have the same charge, the dipole moment will be zero.

o EX: CO 2 When a molecule forms, if two dipole moments with polarity are opposite, the molecule is not polar, if they are not directly opposite the molecules are polar.

Linear Electron-Domain Geometry • • Molecular: Linear Domains: 2 Total o All bonding pairs • • • Bond Angles: 180 o Hybridization: sp Polar? No

Trigonal Planar Electron-Domain Geometry • • • • • Molecular: trigonal planar Domains: 3 Total o All bonding pairs Bond Angles: 120 o Hybridization: sp 2 Polar? No

Trigonal Planar Electron-Domain Geometry • • • • • Molecular: bent Domains: 3 Total o 2 bonding pairs o 1 nonbonding pair Bond Angles: 120 o Hybridization: sp 2 Polar? Yes

Tetrahedral Electron-Domain Geometry • • • • • Molecular: Tetrahedral Domains: 4 Total o All bonding pairs Bond Angles: 109.5

o Hybridization:sp 3 Polar? No

Tetrahedral Electron-Domain Geometry • • • • • Molecular: Trigonal Pyramidal Domains: 4 Total o 3 bonding pairs o 1 nonbonding pair Bond Angles: 109.5

o Hybridization: sp 3 Polar? Yes

Tetrahedral Electron-Domain Geometry • • • • • Molecular: Bent Domains: 4 Total o 2 bonding pairs o 2 nonbonding pairs Bond Angles: 109.5

o Hybridization:sp 3 Polar? Yes

Trigonal Bipyramidal- Electron Domain Geometry • • • • • Molecular: Trigonal Bipyramidal Domains: 5 Total o All bonding pairs Bond Angles: 120 o ,90 o Hybridization: sp 3 d Polar? No

Trigonal Bipyramidal- Electron Domain Geometry • • • • • Molecular: Seesaw Domains: 5 Total o 4 bonding domains o 1 nonbonding domains Bond Angles: 120 o ,90 o Hybridization: sp 3 d Polar? Yes

Trigonal Bipyramidal- Electron Domain Geometry • • • • • Molecular: T-shaped Domains: 5 Total o 3 bonding domains o 2 nonbonding domains Bond Angles: 120 o ,90 o Hybridization: sp 3 d Polar? Yes

Trigonal Bipyramidal- Electron Domain Geometry • • • • • Molecular: Linear Domains: 5 Total o 4 bonding domains o 1 nonbonding domains Bond Angles: 120 o ,90 o Hybridization: sp 3 d Polar? Yes

Octahedral- Electron Domain Geometry • • • • • Molecular: Octahedral Domains: 6 Total o 6 bonding domains o 0 nonbonding domains Bond Angles: 90 o Hybridization: sp 3 d 2 Polar? No

Octahedral- Electron Domain Geometry • • • • • Molecular: Square Pyramidal Domains: 6 Total o 5 bonding domains o 1 nonbonding domains Bond Angles: 90 o Hybridization: sp 3 d 2 Polar? Yes

Octahedral- Electron Domain Geometry • • • • • Molecular: Square Planar Domains: 6 Total o 4 bonding domains o 2 nonbonding domains Bond Angles: 90 o Hybridization: sp 3 d 2 Polar? No

• • • Sigma Bond Pi Bond covalent bond in which electron • covalent bond in which electron density is density is concentrated along concentrated above the internuclear axis.

and below the Electron densities overlap Strongest type of • internuclear axis. Weaker than sigma bonds covalent bond

Problems 1. What are the electron-domain and molecular geometries of a molecule that has the following electron domains on its central atom?

A) 4 bonding, 0 non bonding B) 3 bonding, 1 non bonding C) 2 bonding, 2 non bonding

Problems 2. Do the electron-domain and molecular geometry, bond angles, polarity, hybridization and resonance structures for: A) KrF 2 B) SiCl 4 C) BCl 3