L12S08 Bonding_Lewis structures

L12S08 Bonding_Lewis structures - Chem 1A L12:...

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Unformatted text preview: Chem 1A L12: "Chemical Bonds, Lewis Structures" Lab 4: How the Nose Knows (this week) Goal: Develop a theory of how molecular shapes and functional groups affect our sense of smell. Tools and Skills: : Smell sample compounds, collect observations, draw Lewis dot structures, develop a model for smell. M.Kubinec,A.Pines,Nitsche L12-1 The Periodic Table s d p Hayden-McNeil Specialty Products M.Kubinec,A.Pines,Nitsche f L12-2 M.Kubinec,A.Pines,Nitsche L12-3 M.Kubinec,A.Pines, H.Nitsche 1 Chem 1A L12: "Chemical Bonds, Lewis Structures" The Pauling Electronegativity Values M.Kubinec,A.Pines,Nitsche L12-4 Electronegativity Zeff n - Ionic > 2.0 Na+ClPartly Ionic ~ 0.4-2.0 H+Cl0.4Covalent Cl - Cl < 0.4 Electronegativity + Na ~0.9 H ~ 2.2 Cl ~ 3.2 M.Kubinec,A.Pines,Nitsche L12-5 Ionization Energy, Electron Affinity X X + eX+ + e- IE X EA + e- mol-1) EA (kJ mol-1) IE (kJ M Na K Rb 496 419 403 -53 -48 -47 mol-1) EA (kJ mol-1) IE (kJ X Cl Br I 125 114 100 1 0 8 349 325 295 L12-6 M.Kubinec,A.Pines,Nitsche M.Kubinec,A.Pines, H.Nitsche 2 Chem 1A L12: "Chemical Bonds, Lewis Structures" ChemQuiz 11.0 For which X does H2 + X2 2HX H X X H H X X H release the most energy? A) Cl M.Kubinec,A.Pines,Nitsche B) Br C) I L12-7 M.Kubinec,A.Pines,Nitsche L12-9 Summary M.Kubinec,A.Pines, H.Nitsche 3 Chem 1A L12: "Chemical Bonds, Lewis Structures" Lewis Electron Dot Structures Valence Electrons Stable Octet H . He : . . . Li. Be . .B . . C . .N . :O . : F. :Ne : . . . : : : : : : : : : : : : : : : : : : . . . Na. Mg. .Al . .Si . . . . :S . : Cl . :Ar: P . . M.Kubinec,A.Pines,Nitsche L12-11 ChemQuiz 12.1 Which element forms a bromide that is ~80% Br by mass? ~ atomic mass Br 80 Ca 40 K 40 Ne 20 A) Ne M.Kubinec,A.Pines,Nitsche B) K C) Ca L12-12 Ionic Bonding (Electron Transfer) e- + Coulomb + - Attraction Li. + : F. Li + + :F: : : : : : Na. + :Cl. M.Kubinec,A.Pines,Nitsche M.Kubinec,A.Pines, H.Nitsche 4 : : : : : : : Na + :Cl : - MgCl2 L12-14 Chem 1A L12: "Chemical Bonds, Lewis Structures" ChemQuiz 12.2 The r at which e- jumps to form an ionic bond varies. For which Chloride formation is r greatest ? e- r A) Li M.Kubinec,A.Pines,Nitsche B) Na C) K L12-15 Crystal Formation M.Kubinec,A.Pines,Nitsche L12-17 Covalent Bonding (Electron Sharing) Molecular Orbitals H. + : : : : .H : : : : H:H : Cl: Cl : : : : : : : : : Cl . + . Cl : M.Kubinec,A.Pines,Nitsche Cl: H Cl: L12-18 : : : M.Kubinec,A.Pines, H.Nitsche 5 Chem 1A L12: "Chemical Bonds, Lewis Structures" (a) The Interaction of Two Hydrogen Atoms (b) Energy Profile as a Function of the Distance Between the Nuclei of the Hydrogen Atoms M.Kubinec,A.Pines,Nitsche L12-19 (a) The Charge Distribution in the Water Molecule. (b) The Water Molecule in an Electric Field M.Kubinec,A.Pines,Nitsche L12-20 The HCl Molecule Has a Dipole Moment M.Kubinec,A.Pines,Nitsche L12-21 M.Kubinec,A.Pines, H.Nitsche 6 Chem 1A L12: "Chemical Bonds, Lewis Structures" Octet Rule H H C H H H N H H Exceptions :F B F: : : : : : : :N :C : : O : : : : O N: O: :F: F .. F Xe .. : F M.Kubinec,A.Pines,Nitsche : : M.Kubinec,A.Pines,Nitsche : A) C::O ::O H B) C:::O: :::O : H C) H:C:O:H : : : : : : How many bonds are needed to complete the structure of the cyanide ion?: ion?: 1) 0 M.Kubinec,A.Pines,Nitsche M.Kubinec,A.Pines, H.Nitsche 7 : : H .. F SF6 L12-22 ChemQuiz 12.3 Which is the correct Lewis electron dot structure of Formaldehyde? H CH2O L12-23 ChemQuiz 12.4 - C N 2) 1 3) 2 L12-25 Chem 1A L12: "Chemical Bonds, Lewis Structures" Lecture Complete M.Kubinec,A.Pines,Nitsche L12-27 M.Kubinec,A.Pines, H.Nitsche 8 ...
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This note was uploaded on 04/03/2008 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at University of California, Berkeley.

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