Chem 112 Exam AID Course Pack

Is considered to be sp2 hybridized o one combination

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Unformatted text preview: of shared electrons between two atoms Bond Length - The distance between two atomic nuclei BOND ORDER INCREASES AS BOND LENGTH DECREASES i.e. Triple bonds (Bond Order of 3) are shorter than double bonds (Bonder order of 2) Bond Energies: - Bond energies can be used to determine reaction energies Ethan Newton & Barry Zhang for SOS Winter 2012 12 - To figure out the changes in enthalpy, we subtract the energies of the products from the energies of the reactants ΔHrxn= ΣD(reactants) - ΣD(products) Chemical Bonding: - - - - The manner in which orbitals interact when atoms come together in a bond The overlap of orbitals consists of the sharing of electrons Orbitals must have similar energies and correct orientation in order to interact in a favourable fashion Covalent bonds are formed between UNPAIRED ELECTRONS on adjacent atoms Hybridization: - Combining two orbitals o i.e. sp2 combines the s orbital and two p orbitals §༊ Results in an orbital lower in energy than a p orbital for the same molecule, but higher than the s orbital o The same number of electrons remain in hybridized orbital as in those contributing; however, they are now all equal in energy o The total number of electrons contributing to the orbital, the total number of bonds can be formed to the atom §༊ i.e. sp3 hybridized Carbon can form four bonds since it contains 4 electrons in the hybridized orbital (3p orbitals and 1s orbital coming together) Relating Hybridization to VSEPR: - - Based on the number of bonds surrounding a central atom, it is possible to determine its hybridization o Trigonal planar geometry exhibits sp2 hybridization on the central atom §༊ Explained by the fact that three bonds are being formed from the atom. (one CAN be a double bond) §༊ e.g Ethene (CH2=CH2) OR simply three single bonds BH3 o Remember: Lone pairs contribute to a molecules hybridization o When a molecule has more than 4 bonds around it, the molecule will contain some ‘d’ character o I.e. PCl5 ; phosphorous will exhibit sp3d hybridization Single bonds consist of a σ bond Ethan Newton & Barry Zhang for SOS Winter 2012 13 - - - Double bonds consist of one σ bond and one π bond Triple bonds consist of two π bonds and one σ bond REMEMBER: Only orbitals which are in phase (thereby exhibiting the same...
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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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