Ch. 6: Chemical Bonding II: Valence Bond and Molecular Orbital Theory

Valence Bond Theory

Theory explaining bond formation via orbital interaction.

Hybridization

Mixing of atomic orbitals to form new orbitals.

Sigma Bond

Bond formed by head-on orbital overlap.

Pi Bond

Bond formed by sidewise orbital overlap.

sp3 Hybridization

Combination of one s and three p orbitals.

sp2 Hybridization

Combination of one s and two p orbitals.

sp Hybridization

Combination of one s and one p orbital.

Bond Order

Half the difference between bonding and antibonding electrons.

Paramagnetic

Substance with unpaired electrons, attracted to magnets.

Diamagnetic

Substance with all paired electrons, repelled by magnets.

LCAO Method

Linear combination of atomic orbitals to form MOs.

Molecular Orbital Theory

Theory using wave functions to describe molecular bonding.

Constructive Interference

Wave functions combine to lower energy, forming bonding MOs.

Destructive Interference

Wave functions combine to raise energy, forming antibonding MOs.

Bonding Molecular Orbital

Lower energy orbital formed by constructive interference.

Antibonding Molecular Orbital

Higher energy orbital formed by destructive interference.

Tetrahedral Geometry

Geometry with 109.5° bond angles and four groups.

Trigonal Planar Geometry

Geometry with 120° bond angles and three groups.

Octahedral Geometry

Geometry with 90° bond angles and six groups.

Bond Length

Distance between nuclei of bonded atoms.

Bond Strength

Energy required to break a bond.

Resonance

Delocalization of electrons across multiple structures.

Magnetic Behavior

Response of a substance to a magnetic field.

Quantum Mechanical Orbitals

Regions where electrons are likely found.

Electron Spin Pairing

Electrons must have opposite spins in orbitals.

Geometry of Molecules

Shape determined by orbital interactions and hybridization.

Delocalization

Electrons shared across multiple atoms in a molecule.