Lecture 7 - Lecture 7: Periodic Properties of the Elements...

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Unformatted text preview: Lecture 7: Periodic Properties of the Elements p. 202 11/20/2007 9:09:57 PM ET Breaking News Bulletin: Crude oil price hits record $99.29 a barrel in electronic trading http Cowboy Chemistry The Study of Vigorous Chemical Reactions “It’s not a perfect world. Get over it!!” Energy Chemical Reactions Ea Reactants Kinetics Ea = Activation Energy 2H2 + ΔH 2 2H2O Thermodynamics O Exo Exo Products Reaction Coordinate MnO2: Electron transfer catalyst 2 H2 O2 --------> 2 H2O + O2 The Periodic Table The s d p © Hayden-McNeil Specialty Products f Periodic Properties depend on…. -Effective nuclear charge -Size of valance orbital -Filled/half-filled orbital stability -Electron-electron repulsion -Penetration(s>p>d>f) Effective Nuclear Charge Table 5-3, p. 189 : Valence Orbitals Atomic Radius Largest atomic radius? Smallest atomic radius? Largest atomic radius? Cs 2.62 A0 Smallest atomic radius? He 0.31 A0 Ionization Energy, Electron Affinity Ionization X X + e­ X + e­ X ­ + IE EA Rb 403 ­47 e­ M (kJ) (kJ) Na 496 ­53 K 419 ­48 IE IE EA (kJ) (kJ) X Cl 1251 ­349 Br 1140 ­325 I 1008 ­295 EA Trend in Ionization Energy 2500 2000 1500 1 0 0 0 1s1 1s2 2p6 2p 2p4 2p3 2p5 2s2 2s1 2p2 2p1 500 Ionization Energy (kJ) 0 3s1 C N O F Ne Na H H e Li Be B Highest Ionization Potential? Lowest Ionization Potential? Highest Ionization Potential? He 2372 kJ/mol Lowest Ionization Potential? Cs 377 kJ/mol Highest electron affinity? Lowest electron affinity? Highest electron affinity? Cl 349 kJ/mol (n.b. Sign) Lowest electron affinity? Mg -14 kJ/mol Electronegativity Zeff n ­ Δ > 2.0 Ionic Na Cl­ Electronegativity Partly Ionic Δ ~ 0.4­2.0 Hδ +Clδ ­ Δ < 0.4 Covalent Cl ­ Cl + Na ~0.9 H ~ 2.2 Cl ~ 3.2 Electronegativity: attraction of an atom for valence electrons in a chemical bond Most electronegative element ? Least electronegative element ? Most electronegative element ? F 3.98 Least electronegative element ? Cs 0.79 ChemQuiz MT1.1 Which is the heaviest metal ? Which is the heaviest metal ? . LED ?? ChemQuiz MT1.1 Which is the heaviest(densest) metal??? Which is the heaviest(densest) metal??? Os 22.587 kg/L Os>Ir>Pt>Rb>Np Lead 11.4 kg/L . This lecture is Terminated!!! Happy Thanksgiving!!! Be SAFE!! It’s not a perfect world… ...
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This note was uploaded on 09/29/2009 for the course CHEM 4a taught by Professor Gordon during the Fall '06 term at University of California, Berkeley.

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