Polarity and Reactivity Halogens are more electronegative than C. Carbon-halogen bond is polar,so carbon has partial positive charge. Carbon can be attacked by a nucleophile. Halogen can leave with the electron pair. H+ 6+ HC一CI H chloromethane EPM of chloromethane Copyright 2005 Pearson Prentice Hall.Inc. Polarity and Reactivity ◼Halogens are more electronegative than C. ◼Carbon-halogen bond is polar, so carbon has partial positive charge. ◼Carbon can be attacked by a nucleophile. ◼Halogen can leave with the electron pair