23. Valence Theory and Constitutional Structure (1858)

Freshman Organic Chemistry (CHEM 125)

Youthful chemists Couper and Kekulé replaced radical and type theories with a new approach involving atomic valence and molecular structure, and based on the tetravalence and self-linking of carbon. Valence structures offered the first explanation for isomerism, and led to the invention of nomenclature, notation, and molecular models closely related to those in use today.

00:00 - Chapter 1. Archibald Couper: "Look to the Elements"
10:25 - Chapter 2. Tetravalence and Self-Linking of Carbon
19:39 - Chapter 3. Kekule's Advancements in Chemical and Molecular Notation
38:32 - Chapter 4. 3-D Molecular Models: From Brass Strips to Croquet-Balls

Complete course materials are available at the Open Yale Courses website: http://open.yale.edu/courses

This course was recorded in Fall 2008.