Chem 112 Exam AID Course Pack

Boyles law p1v1 p2v2 3charless law the volume of a gas

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Unformatted text preview: sign) can overlap with each other to form a bonding orbital §༊ Orbitals which are out of phase will contribute to antibonding orbitals Molecular Orbitals: - - - - - Molecular orbitals allow electrons to be shared in a covalent bond The number of molecular orbitals is the same as the number of atomic orbitals combined - when two MOs are formed from two AOs, 1 MO is bonding and has a lower energy than the AOs and 1 MO is anti- bonding and has higher energy than the AOs Electrons are added to the lowest energy level o Only valence shell electrons are shown The maximum number of electrons that can contribute to a molecular orbital is 2 We define the bond order in terms of bonding and anti- bonding orbitals o Simply subtract number of antibonding orbitals from number of bonding orbitals MO Diagrams: - - - - - Bonding orbitals are always lower in energy than their associated anti- bonding orbitals σ* is ALWAYS the least stable orbital in a Molecular Orbital Diagram The σ2S orbital and the σ2P orbital are always lower in energy than the σp and π orbitals Degenerate Orbitals are those which have the same energy o Often result when multiple p orbitals are coming together o Degenerate orbitals get one electron each, before the electrons are paired o Paramagnetic molecules are those with unpaired electrons Drawn by indicating the contributing electrons from each atom involved in the bond on each side, and matching those with similar energies to form the Molecular Orbital in the middle. o The energies of the MOs are shifted toward those of the atomic orbitals for atoms with the highest electronegativity §༊ Consequently, antibonding orbitals are shifted towards the atomic orbitals for the atoms with lower electronegativity Delocalized Electrons: Ethan Newton & Barry Zhang for SOS Winter 2012 14 - When a pair of π electrons are shared over three electrons o 3 p orbitals that are combined o Occurs in molecules such as ozone and benzene §༊ Each oxygen in ozone and each carbon in benzene is considered to be sp2 hybridized o One combination of p orbitals will result in a bonding orbital, one will result in an anti- bonding orbital, and the third combination will result in a non- bonding orbital §༊ Non- bonding orbitals result from p- orbitals...
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This note was uploaded on 10/02/2012 for the course CHEM 112 taught by Professor Carran during the Winter '08 term at Queens University.

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