0When a covalent bond breaks, under the influence of incoming electrophile or nucleophile, it happens in two ways
1.Heterolytic fission
2.Homolytic fission
Homolytic fission : when a covalent bond breaks, the two electrons of bond are equally divided between two atom forming bond. The new species formed both carries single unpaired electron and are called free radicals.
Heterolytic fission : when a covalent bond breaks, two electrons of bond are unequally divided among atom of compound. One atom get both electrons and become negatively charged, called nucleophile. Other atom which do not get any electron get positively charged and called electrophile.
