CHEM 140A Chapter Notes - Chapter 3: Unpaired Electron, Electronegativity, Hyperconjugation
19 Mar 2018
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Ch 3 bond dissociation energies, radical halogenation, and relative reactivity. Bond dissociation energy, dh, is a quantitative measure of bond strength. Two bonding electrons divide equally between the two participating atoms or fragments. Fragments with an unpaired electron and are composed of more than one atom are called radicals. Very reactive and so cannot be isolated but they form intermediates in many reactions. Heterolytic cleavage is when the entire bonding pair is donated to one of the atoms. Restricted to situations where the electronegativities of atoms a and b and the groups attached to them stabilize positive and negative charges, respectively. Bonds are strongest when made by overlapping orbitals that are closely matched in energy textbook notes page 1. Bonds are strongest when made by overlapping orbitals that are closely matched in energy and size. The stability of radicals determines the c-h bond strengths.
