Exam #4 Review SessionChem 111, Fall 2009

Bond Properties

• Length• Order• Strength• Polarity

Periodic Table

Bond Properties

• Which atom is more electronegative? B or C N or P

• Which bond is most polar? C-C or C-O or C-F C-O or C-S

• Which bond is the longest? C-O or C-F C-O or C=O

Lewis StructuresWhy We Love Them (and you know we do!)

• Drawing a Lewis Structure:– Calculating formal charge– Determining which resonance structure is best

• Use Lewis Structure to:– Determine bond order– Determine electron pair and molecular geometry– Calculate formal charge and oxidation numbers– Determine hybridization and bond types

Draw a Lewis Structure for CS2

Periodic Table

Formal Charges and Oxidation Numbers

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Molecular Geometry

# Structural Pairs

Electron Pair Geometry Angle

Molecular Geometry

Number of Lone Pairs

0 1 2 3

4 Linear 180° Linear

3 trigonal planar 120° trigonal planar bent bent

4 tetrahedral 109.5° tetrahedral trigonal pyramidal bent

5 trigonal bipyramidal

90° 120°180°

trigonal bipyramidal see-saw T-shaped Linear

6 octahedral 90°180° octahedral square

pyramidalsquare planar

Molecular Geometry for Propane, 1-Propanol, and Propene

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Hybridization and Bond Types for Propane, 1-Propanol, and Propene

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Hybrid Orbital Geometry