Download Lewis formula Electron Pairs Electron Pair Molecular Example Total

Chemistry 101 Chapter 10 Lewis formula Electron Pairs Total Bonding Lone Electron Pair Geometry Molecular Geometry Example AX2 X : A : X 2 2 0 F¾Be¾F Linear Linear Bond Angle = 180 0 O = C = O Nonpolar Treat double bonds as single bonds AX3 F X . . A : X . . X B 3 3 0 Trigonal Bond Angle = 120 0 planar Nonpolar Trigonal Planar
5 F F Chemistry 101 Chapter 10 Lewis formula Electron Pairs Total Bonding Lone AX2E E = lone pair . . X : A :: X or . . X :: A : X Treat double bonds as single bonds AX4 X . . X : A : X . . X Electron Pair Geometry Molecular Geometry Example S 3 2 1 O O Trigonal Bent (angular) planar Bond Angle » 120 0 Polar Cl C 4 4 0 Cl Cl Cl Tetrahedral Tetrahedral Bond Angle » 109.5 0 Nonpolar
6 Chemistry 101 Lewis formula AX3E E = lone pair . . X : A : X . . X Chapter 10 Electron Pairs Total Bonding Lone 4 3 Electron Pair Geometry 1 Example N H H H Tetrahedral AX2E2 . . X : A : . . X Molecular Geometry 4 2 Trigonal Pyramidal Bond Angle »109.5 0 Polar O H H 2 Tetrahedral 7 Bent (Angular) Bond Angle »109.5 0 Polar
Chemistry 101 Chapter 10 Lewis formula Electron Pairs Total Bonding Lone Electron Pair Geometry Molecular Geometry Example AX5 Cl X X Cl X A Cl 5 5 P 0 Cl Cl X X Trigonal Trigonal bipyramidal bipyramidal Bond Angles: 120 0 (3) and 90 0 (6) Nonpolar PCl5 SF4 AX4E F F X . . X : A : X . . X S F 5 4 1 Trigonal bipyramidal 8 Seesaw Bond Angles: 120 0 , 90 0 , and 180 0 Polar
F Chemistry 101 Chapter 10 Lewis formula Electron Pairs Total Bonding Lone AX3E2 X . . X : A . . X Electron Pair Geometry Molecular Geometry ClF3 F F 5 3 Cl 2 Trigonal T­shaped bipyramidal Bond Angles: 90 0 Polar AX2E3 X . . A . . X Example F XeF2 F 5 2 3 Xe Linear Trigonal Bond Angle = 180 0 bipyramidal Nonpolar
9 F Chemistry 101 Chapter 10 Lewis formula Electron Pairs Total Bonding Lone Electron Pair Geometry Molecular Geometry Example AX6 SF6 X X F X A X F 6 6 0 S X F X Octahedral F IF5 F F F I F F X X 6 5 1 A X F Octahedral Bond Angle = 90 0 Nonpolar AX5E X F X Octahedral 10 Square pyramidal Bond Angle: 90 0 Polar
Chemistry 101 Chapter 10 Lewis formula Electron Pairs Total Bonding Lone AX4E2 X X A X X 6 4 Electron Pair Geometry Molecular Geometry Example XeF4 2 Octahedral Square planar Bond Angle: 90 0 Nonpolar
11 F F Xe F F Chemistry 101 Chapter 10 SUMMARY Symmetrical Arrangement Asymmetrical Arrangement Polar Bonds Nonpolar Molecule Polar Bonds Polar Molecule Linear Bent Trigonal Planar planar Trigonal pyramidal Tetrahedral Seesaw Trigonal bipyramidal T­shaped Octahedral Square pyramidal Square planar
12 Chemistry 101 Chapter 10 BOND ANGLES
· Bond angles between atoms can be approximately predicted from the VSEPR model.
· Some deviations from the predicted bond angles have been determined experimentally. These deviations are caused by 2 factors: 1. Effect of Lone Pairs A lone pair tends to require more space than a bonding pair Reason: A lone pair of electrons is attracted to only one atomic core, whereas a bonding pair is attracted to two. The lone pair is larger, while the bonding pair is drawn more tightly to the nuclei. Lone pair Bonding Pair Lone pairs repel each other stronger than Bonding Pairs. Result: The repulsions between electron pairs depend on the type of electron pairs involved. REPULSION INCREASES Bonding Pairs Bonding Pairs Bonding Pairs Lone Pairs Weakest Repulsion Lone Pairs Lone Pairs Strongest Repulsion
13 Chemistry 101 Chapter 10 CH4 NH3 H2O Tetrahedral Tetrahedral Tetrahedral 109.5° 109.5° 109.5° Bonding Pairs 4 3 2 Lone Pairs 0 1 2 109.5° 107° 105° Electron Pair Geometry Expected Bond Angle Actual Bond Angle 2. Effect of Multiple Bonds Muiltiple bonds require more space than single bonds because of the greater number of electrons: Electron Pair Geometry: Trigonal Planar Expected Bond Angle: 120 0 Actual Bond Angle: 116 0 Reason: C = O C ¾ H Stronger Repulsion C ¾ H C ¾ H Weaker Repulsion
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