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: CO2
• 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
• Hybridization: sp
• Polar? No
o
Trigonal Planar Electron-Domain Geometry
• Molecular: trigonal
planar
• Domains: 3 Total
o All bonding pairs
• Bond Angles: 120
• Hybridization: sp
• Polar? No
o
2
Trigonal Planar Electron-Domain Geometry
• Molecular: bent
• Domains: 3 Total
•
•
•
o 2 bonding pairs
o 1 nonbonding pair
Bond Angles: 120o
Hybridization: sp2
Polar? Yes
Tetrahedral Electron-Domain Geometry
• Molecular:
Tetrahedral
• Domains: 4 Total
o All bonding pairs
• Bond Angles: 109.5
• Hybridization:sp
• Polar? No
o
3
TetrahedralElectron-Domain Geometry
• Molecular: Trigonal
Pyramidal
• Domains: 4 Total
•
•
•
o 3 bonding pairs
o 1 nonbonding pair
Bond Angles: 109.5o
Hybridization: sp3
Polar? Yes
Tetrahedral Electron-Domain Geometry
• Molecular: Bent
• Domains: 4 Total
•
•
•
o 2 bonding pairs
o 2 nonbonding pairs
Bond Angles: 109.5o
Hybridization:sp3
Polar? Yes
Trigonal Bipyramidal- ElectronDomain Geometry
• Molecular: Trigonal
Bipyramidal
• Domains: 5 Total
o All bonding pairs
• Bond Angles:
120 ,90
• Hybridization: sp d
• Polar? No
o
o
3
Trigonal Bipyramidal- ElectronDomain Geometry
• Molecular: Seesaw
• Domains: 5 Total
o 4 bonding domains
o 1 nonbonding
domains
• Bond Angles:
120 ,90
• Hybridization: sp d
• Polar? Yes
o
o
3
Trigonal Bipyramidal- ElectronDomain Geometry
• Molecular: T-shaped
• Domains: 5 Total
o 3 bonding domains
o 2 nonbonding
domains
• Bond Angles:
120 ,90
• Hybridization: sp d
• Polar? Yes
o
o
3
Trigonal Bipyramidal- ElectronDomain Geometry
• Molecular: Linear
• Domains: 5 Total
o 4 bonding domains
o 1 nonbonding
domains
• Bond Angles:
120 ,90
• Hybridization: sp d
• Polar? Yes
o
o
3
Octahedral- Electron Domain
Geometry
• Molecular:
Octahedral
• Domains: 6 Total
o 6 bonding domains
o 0 nonbonding
domains
• Bond Angles: 90
• Hybridization: sp d
• Polar? No
o
3 2
Octahedral- Electron Domain
Geometry
• Molecular: Square
Pyramidal
• Domains: 6 Total
o 5 bonding domains
o 1 nonbonding
domains
• Bond Angles: 90
• Hybridization: sp d
• Polar? Yes
o
3 2
Octahedral- Electron Domain
Geometry
• Molecular: Square
Planar
• Domains: 6 Total
o 4 bonding domains
o 2 nonbonding
domains
• Bond Angles: 90
• Hybridization: sp d
• Polar? No
o
3 2
Sigma Bond
• covalent bond in
•
•
which electron
density is
concentrated along
the internuclear axis.
Electron densities
overlap
Strongest type of
covalent bond
Pi Bond
• covalent bond in
•
which electron
density is
concentrated above
and below the
internuclear axis.
Weaker than sigma
bonds
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) KrF2
B) SiCl4
C) BCl3