5.111SC | Fall 2014 | Undergraduate

Principles of Chemical Science

Unit II: Chemical Bonding & Structure

Lecture 12: The Shapes of Molecules: VSEPR Theory

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Image excerpted from Lecture 12 Notes 

  1. The Shapes of Molecules: VSEPR Theory
    1. Molecules without Lone Pairs
    2. Molecules with Lone Pairs

Lecture Video

Valence shell electron pair repulsion or VSEPR theory can be used to predict molecular geometry. The theory is based on Lewis structures and the simple idea that that the preferred geometry around a central atom is the one that minimizes electron repulsion. Chemist Stefanie Sydlik tells us how she uses VSEPR theory to design sensors that are capable of detecting landmines.

Lecture Notes

Notes for Lecture 12 (PDF)

Clicker Questions

Lecture 12 Clicker Questions (PDF)

Textbook Reading

The Basic VSEPR Model Section 3.1 Section 3.1
Molecules with Lone Pairs on the Central Atom Section 3.2 Section 3.2

Detecting Explosives To Save Lives In War Zone

Stefanie Sydlik explains how her research on designing sensors for explosives depends on the principles of VSEPR (valence shell electron pair repulsion) theory. Stefanie’s sensor design amplifies small-scale changes in bond angles following interaction with a target molecule, and she hopes that her work will lead to better detectors for landmines and improvised explosive devices.

Stefanie Sydlik’s Personal Story

Stefanie Sydlik describes how an exciting “Take Your Daughter to Work Day” convinced her to become a chemist. She considers chemistry to be a bridge between biology and physics that can help explain observations made in everyday life.

Problems and Solutions

Problems for Lecture 12 (PDF)

Solutions for Lecture 12 (PDF)

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Fall 2014
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