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CHEM 125A - Freshman Organic Chemistry I

Lecture 23 - Valence Theory and Constitutional Structure (1858). Youthful chemists Couper and Kekule 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. (from oyc.yale.edu)

Lecture 23 - Valence Theory and Constitutional Structure (1858)

Time Lecture Chapters
[00:00:00] 1. Archibald Couper: "Look to the Elements"
[00:10:25] 2. Tetravalence and Self-Linking of Carbon
[00:19:40] 3. Kekule's Advancements in Chemical and Molecular Notation
[00:38:33] 4. 3-D Molecular Models: From Brass Strips to Croquet-Balls

References
Lecture 23 - Valence Theory and Constitutional Structure (1858)
Instructor: Professor J. Michael McBride. Resources: Professor McBride's website resource for CHEM 125 (Fall 2008). Transcript [html]. Audio [mp3]. Download Video [mov].

Go to the Course Home or watch other lectures:

Lecture 01 - How do You Know?
Lecture 02 - Force Laws, Lewis Structures and Resonance
Lecture 03 - Double Minima, Earnshaw's Theorem, and Plum-Puddings
Lecture 04 - Coping with Smallness and Scanning Probe Microscopy
Lecture 05 - X-Ray Diffraction
Lecture 06 - Seeing Bonds by Electron Difference Density
Lecture 07 - Quantum Mechanical Kinetic Energy
Lecture 08 - One-Dimensional Wave Functions
Lecture 09 - Chladni Figures and One Electron Atoms
Lecture 10 - Reality and the Orbital Approximation
Lecture 11 - Orbital Correction and Plum-Pudding Molecules
Lecture 12 - Overlap and Atom-Pair Bonds
Lecture 13 - Overlap and Energy-Match
Lecture 14 - Checking Hybridization Theory with XH3
Lecture 15 - Chemical Reactivity: SOMO, HOMO, and LUMO
Lecture 16 - Recognizing Functional Groups
Lecture 17 - Reaction Analogies and Carbonyl Reactivity
Lecture 18 - Amide, Carboxylic Acid and Alkyl Lithium
Lecture 19 - Oxygen and the Chemical Revolution (Beginning to 1789)
Lecture 20 - Rise of the Atomic Theory (1790-1805)
Lecture 21 - Berzelius to Liebig and Wohler (1805-1832)
Lecture 22 - Radical and Type Theories (1832-1850)
Lecture 23 - Valence Theory and Constitutional Structure (1858)
Lecture 24 - Determining Chemical Structure by Isomer Counting (1869)
Lecture 25 - Models in 3D Space (1869-1877); Optical Isomers
Lecture 26 - Van't Hoff's Tetrahedral Carbon and Chirality
Lecture 27 - Communicating Molecular Structure in Diagrams and Words
Lecture 28 - Stereochemical Nomenclature; Racemization and Resolution
Lecture 29 - Preparing Single Enantiomers and the Mechanism of Optical Rotation
Lecture 30 - Esomeprazole as an Example of Drug Testing and Usage
Lecture 31 - Preparing Single Enantiomers and Conformational Energy
Lecture 32 - Stereotopicity and Baeyer Strain Theory
Lecture 33 - Conformational Energy and Molecular Mechanics
Lecture 34 - Sharpless Oxidation Catalysts and the Conformation of Cycloalkanes
Lecture 35 - Understanding Molecular Structure and Energy Through Standard Bonds
Lecture 36 - Bond Energies, the Boltzmann Factor and Entropy
Lecture 37 - Potential Energy Surfaces, Transition State Theory and Reaction Mechanism