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Ch 10: Chemical Bonding Lewis Dot Structures: dots represent valence electrons

Octet Rule: In chemical bonding, atoms transfer or share electrons to obtain outer shells with eight electrons. Exceptions: H, Li, Be & B (6)

Hmwk: 2, 6, 23, 31, 37, 43, 47, 49, 57, 65, 79, 89, 95 & 105

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Lewis Theory of Chemical Bonding •  In Lewis theory, a chemical bond involves

the sharing or transfer of electrons to attain stable electron configurations for the bonding atoms.

•  If the electrons are transferred, the bond is an ionic bond.

•  If the electrons are shared, the bond is a covalent bond.

•  In either case, the bonding atoms attain stable electron configurations.

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Lewis Structures for

•  Ionic Compounds: e- transferred •  Covalent Compounds: e- shared

•  Atom Arrangement: •  Hydrogens are terminal •  Molecules tend towards symmetry •  Multiple identical atoms- terminal

•  Bonding & Lone-pair electrons •  Bonds: single, double & triple •  Polyatomic ions •  Exceptions: NO, BF3, SF6 & PCl5 •  Resonance: O3 & CO3

2-

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VSEPR Theory & Molecular Geometry

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Electronegativity, Polar Bonds & Polar Molecules

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The degree of bond polarity is a continuous function. The guidelines given here are approximate.

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© 2012 Pearson Education, Inc.

© 2012 Pearson Education, Inc.

Highlight Problem 10.113 •  Draw the Lewis structure

for each of these free radicals, which have been implicated in theories of aging.

•  O2−

•  O− •  OH •  CH3OO(unpaired electron

on terminal oxygen)