The shell structure of a nucleus is important to study their observed characteristic features. The classic magic numbers are successful in explaining the nuclear properties for nuclei lying near the stability line. The advent of radioactive ion beam facilities has permitted to examine nuclei in their extreme proton to neutron ratio. The light exotic nuclei were found to exhibit unique shell closure behaviour which is different from the medium mass nuclei near the stability line. The two nucleon separation energy difference systematics was used as a probe to study the magic character of light nuclei. New proton and neutron magic numbers were predicted among the available even Z isotopes and even N isotones. For certain systems, the classic magic numbers were found to be non-magic, while for some systems the magic property is retained even at the drip lines. The shell closure behaviour predicted is found to depend on the version of the mass table.