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Unformatted text preview: atoms (nonpolar bonds) are nonpolar. 2. Molecules containing unlike atoms (polar bonds) Ø are NONPOLAR if the molecular shape is SYMMETRICAL Ø are POLAR if the molecular shape is ASYMMETRICAL 2 Chemistry 101 Chapter 10 I. NONPOLAR MOLECULES II. POLAR MOLECULES 1. Contain like atoms Contain unlike atoms in asymmetrical arrangement 2.Contain unlike atoms in symmetrical arrangement d 2d+ d d 2d+ d H ¾ H O == C == O F ¾ Be ¾ F d d Cl ¾ Cl F Cl 3d+ N º N B C 4d+ d d d d d F F Cl Cl Cl d+ d H ¾ Cl d + H 2d O d+ H 3d N d+ d+ d+ H H H Centers of positive and negative charges overlap. Electrical charges cancel Nonpolar Bonds Nonpolar Molecules Centers of positive and negative charges do not overlap. Electrical charges do not cancel Polar Bonds Polar Bonds Nonpolar Molecules Polar Molecules (Dipoles) 3 Chemistry 101 Chapter 10 VSEPR MODEL
· Chemists use several models to determine shapes of mo lecules.
· The simplest model is called VSEPR (Valence Shell Electron Pair Repulsion Theory)
· Based on this model, the electron pairs (both bonding and nonbonding) surrounding a central atom are posit ioned as far as possible form each other, thus minimizing electronpair repulsio ns. Number of Electron Pairs Arrangement of Electron Pairs Geometry of Molecule 2 Linerar 3 Trigonal Planar 4 Tetrahedral 5 Trigonal Bipyramidal 6 Octahedral 4...
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