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8.3. Molecular Orbitals. C. Bonding Theory: 1. molecular orbitals: When two atoms combine, the molecular orbital model assumes that their atomic orbitals overlap to produce orbitals that apply to the entire molecule. a. belongs to a molecule as a whole.
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8.3 Molecular Orbitals • C. Bonding Theory: • 1. molecular orbitals: When two atoms combine, the molecular orbital model assumes that their atomic orbitals overlap to produce orbitals that apply to the entire molecule. • a. belongs to a molecule as a whole. • 2. bonding orbital: when a covalent bond is occupied by two electrons.
8.3 Molecular Orbitals • a. sigma bond: two atomic orbitals combine to form a molecular orbital that is symmetrical around the axis connecting two atomic nuclei. • b. pi bond ( bond): bonding electrons are found in sausage-shaped regions above and below the bond axis of the bonded atoms. • F F F--—-F
8.3 Molecular Orbitals • Pi-bonding Molecular Orbital
8.3 VSEPR Theory • 3. VSEPR (valence-shell electron-pair repulsion) theory: repulsion between electron pairs causes molecular shapes to adjust so that the valence-electron pairs stay as far apart as possible.
8.3 VSEPR Theory • a. Nine Possible Molecular Shapes
8.3 Hybrid Orbitals • Hybridization Involving Single Bonds
8.3 Hybrid Orbitals • Hybridization Involving Double Bonds
8.3 Hybrid Orbitals • Hybridization Involving Triple Bonds
Hybrid Orbitals • Simulation 7 Compare sp, sp2, and sp3 hybrid orbitals.
8.3 Section Quiz. • 1. A molecular orbital belongs to a • specific atom. • molecule as a whole. • specific pair of atoms. • central atom.
8.3 Section Quiz. • 2. VSEPR theory enables prediction of 3-dimensional molecular shape because the valence electron pairs • are attracted to each other. • form molecules with only four possible shapes. • stay as far apart as possible. • always form tetrahedral shapes.
8.3 Section Quiz. • 3. Orbital hybridization provides information about • both molecular bonding and molecular shape. • both molecular bonding and bond energy. • neither molecular bonding nor molecular shape. • neither molecular bonding nor bond energy.