Michael McBride continues Yale's Freshman Organic Chemistry II with a lecture on the forces that weaken and strengthen chemical bonds. He opens with a student presentation generalizing fractional-order rate laws, then explains how lone-pair electron repulsion lowers bond dissociation energy. The core of the lecture works through Pauling's definition of electronegativity, showing how differences between atoms make heterolysis (ionic dissociation) easier while making homolysis (radical dissociation) harder, and flags the circularity built into Pauling's own logic for the latter effect. The lecture closes by pivoting from free-radical to ionic reaction mechanisms, examining the electrostatic properties of alkyl halides and alkanes and how solvents influence these reactions. Recorded in spring 2011 as part of the Open Yale Courses series, the talk is chalkboard-based and dense with worked reasoning rather than slides, suited to students already following the course sequence.