Lesson 7: 2.7 VSEPR and Bond Hybridization

How do lone pairs on a central atom alter the structural bond angles of surrounding chemical bonds?
How does the total number of electron domains map directly to the orbital hybridization (sp, sp^2, sp^3) of a central atom?

VSEPR Theory
Electron Domain
Molecular Geometry
Asymmetry
Dipole Moment
Hybridization
Axial/Equatorial

Learning Objective 2.7.A; Suggested Skill 4.A (Model Analysis - Predict/explain phenomena using models)

Integrates everything in Unit 2. Students use Valence Shell Electron Pair Repulsion theory to translate flat Lewis structures into 3D molecular geometries. They must master geometries up to 6 electron domains (including square planar, seesaw, etc.), predict distortions in bond angles due to lone pair repulsions, determine net molecular dipoles, and assign hybridization up to sp^3. Note: dsp^3 and d^2sp^3 hybridizations are excluded by College Board.

Support: Use a hand-held molecular modeling kit or 3D digital simulation software to physically show how a lone pair bends a linear molecule into a bent or trigonal pyramidal shape.
Extension: Provide a large skeletal molecule like caffeine or aspirin. Have students determine the local molecular geometry, bond angles, and orbital hybridization around 4 specific, designated interior atoms.

Consider the chemical species sulfur tetrafluoride, SF4.

1. Draw the Lewis structure and determine its specific 3D molecular geometry name.

2. State the orbital hybridization assigned to the central sulfur atom.

3. Explain whether the molecule is polar or nonpolar.