L15S07_CovalentBond_Resonance 02-21-06

L15S07_CovalentBond_Resonance 02-21-06 - L 15:...

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Unformatted text preview: L 15: "Covalent Bonding, Resonance, Formal Charge Lewis Electron Dot Structures Valence Electrons Stable Octet Previously : : : : : : : : : : Ionic Bonding (Electron Transfer) e- + - - Coulomb : : : : : : + :F: . . . Li. Be . .B . . C . .N . :O . : F. :Ne : . . . . . . Na. Mg. .Al . .Si . . . . :S . : Cl . :Ar: P Mg. . . : : 2000 A.Pines M.Kubinec UCB L3-1 H . He : Attraction Covalent Bonding (Electron Sharing) Molecular Orbitals : : : : Li. + : F. Li + + Na. + : Cl. 2000 A.Pines M.Kubinec UCB Octet Rule H H C H H : : : : : :N :C : : O N: O: Na + :Cl : - MgCl2 L3-4 Exceptions :F O B F: : : : : : : :F: F .. Xe F .. : F H. + : : : .H : : : H:H : Cl: Cl : : : : : 2004 M.Kubinec, A. Pines 2000 A.Pines M.Kubinec UCB : Cl . + . Cl : H Cl: Cl: H N H H .. F SF6 : ChemQuiz 14.3 Which is the correct Lewis electron dot structure of Formaldehyde? 1) C::O ::O H : : : : : H : : L3-6 L15-1 L3-7 2000 A.Pines M.Kubinec UCB 2004 M.Kubinec, A. Pines L15-2 ChemQuiz 14.4 How many bonds are needed to complete the structure of the cyanide ion?: ion?: N - : 2) C:::O: :::O H 3) H:C:O:H 1) 0 2004 M.Kubinec, A. Pines 2) 1 : : : : H CH2O C 3) 2 L15-4 2004 M.Kubinec, A. Pines 1 L 15: "Covalent Bonding, Resonance, Formal Charge Ionic: More electronegative element captures e- Summary + Li :F: Chemical Bonding : : : Resonance, Bond Order Electronegativity Ozone Covalent: Electrons shared equally :Cl: Cl : + Dipole, symmetry Dipole, No Dipole Dipole O O+ - O- -O +O O O C O -2 O O C 1 O 1 3 O 1 : : : : : - Polar Covalent: Unequal sharing, Dipole moment + Carbonate - O O C O O OC O - - O O- O H Cl: Cl: : : : : Benzene L4-4 2000 A.Pines M.Kubinec UCB L3-11 2001 UC Regents Formal Charge (`covalent' electron distribution) Oxidation Number : : Lewis Dot Structure: : : Lewis Dot Structure: Share electrons equally:. N . (5) Compare to atoms: O: N :O: O: (7) Divide up electrons: (More electronegative captures e-) N (2) : : O: N :O: : : - (`Ionic' electron distribution) - : : :O: (8) : : : O: (6) : : : : .N . (5) 0 O: (6) Compare to atoms: .N . (5) +3 : : : : Formal Charge: 2001 UC Regents 2004 M.Kubinec, A. Pines -1 L4-11 Oxidation number: 2001 UC Regents -2 L15-6 L4-10 Chemical Bonding Ionic: More electronegative element captures e- + Li :F: Covalent: Polar: Unequal sharing, Dipole moment Electrons shared equally :Cl: Cl : : : : : Electronegativity : : : : : : : - + Dipole, symmetry Dipole, No Dipole Dipole + H Cl: Cl: : : : : 2004 M.Kubinec, A. Pines L15-7 ChemQuiz 15.1 + - Which of the following molecules is transparent to microwaves? microwaves? 1) C O 2) O=C=O O 3) H C H 2004 M.Kubinec, A. Pines L15-8 2004 M.Kubinec, A. Pines 2 L 15: "Covalent Bonding, Resonance, Formal Charge Resonance, Bond Order Ozone O - O O C O O O C - O O O C O O O C 1 O 2- 1 3 Carbonate - O O O O - - O O - O O 1 Benzene 2004 M.Kubinec, A. Pines L15-10 ChemQuiz 15.2 How does the NO bond order change in the process: nitrite O N O O N O2 - nitrate N O3 - O O N 1) Increase 2004 M.Kubinec, A. Pines 2) Same 3) Decreases L15-11 (`covalent' electron distribution) covalent' Formal Charge : : Lewis Dot Structure: Share electrons equally: .N . (5) Compare to atoms: O: N :O: : : - : : : O: (7) .N . (5) 0 : : : : O: (6) Formal Charge: 2004 M.Kubinec, A. Pines -1 L15-13 2004 M.Kubinec, A. Pines 3 L 15: "Covalent Bonding, Resonance, Formal Charge ChemQuiz 15.3 How does the Formal Charge of nitrogen change for the process: NO2 - O N - O N O3 - O N O O 1) Increase 2004 M.Kubinec, A. Pines 2) Same 3) Decreases L15-14 ChemQuiz 15.4 What is the S-O bond order in the sulfate ion? O O S O O -2 1) 1 2004 M.Kubinec, A. Pines 2) 1.5 3) 2 L15-16 Lecture Complete 2004 M.Kubinec, A. Pines L15-18 2004 M.Kubinec, A. Pines 4 ...
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This note was uploaded on 08/19/2009 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at University of California, Berkeley.

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