CHEM 213 Chapter Notes - Chapter 13.4-13.7: Unpaired Electron, Allyl Group, Pi Bond
20 Feb 2017
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The propenyl cation is more stable than a secondary carbocation and almost as stable as a tertiary carbocation. Carbocation stability: substituted allylic > 3 > allyl > 2 > 1> vinyl. Rules for resonance: 1. resonance only exists in theory on paper, 2. you can only move electrons, you can"t move protons! Generally, when e- are moved, usually they are only pi bonds and lone pairs: 3. all structures must be proper lewis structures. Elements for the rst major row of the periodic table can"t have more than 8 e- in their valence shell: 4. all resonance structures must have the same number of unpaired electrons. Estimating stability of resonance: 1. the more covalent bonds, the more stable. Ex. more double bonds = more stable: 2. structures with complete valence shells are generally more stable, 3. charge separation decreases stability.
