Chemical Properties of Alkyl Halides

The alkyl halides are very reactive; the sequence of reactivity is as follow:

            Iodide > Bromide > Chloride (Nature of the halogen atom)

            Tertiary > Secondary > Primary (kind of the halogen molecules)

            In between the first alkyl halide, the sequence of reactivity is:, etc.

The high reactivity of alkyl halides may be explained in terms of the nature of   bond that is highly polarised covalent bond because of large dissimilarity in the electronegativities of carbon and halogen molecules. The halogen is much more electronegative as compared to carbon and tends to pull the electrons away from carbon that is halogen comprise a small negative charge and carbon a small positive charge.