question_answer

Among the elements K, Mg, C and N which would show the maximum difference in the first and second ionization enthalpies.

Answer:

                The electronic configurations of the elements are: \[K(Z=19):\,\,{{[Ar]}^{18}}\,4{{s}^{1}};\,\,\,Mg(z=12):\,\,{{[Ne]}^{10}}\,3{{s}^{2}}\] \[C(Z=6)\,:\,\,{{[He]}^{2}}2{{s}^{2}}2{{p}^{6}};\,N(Z=7)\]\[:\,\,{{[He]}^{2}}2{{s}^{2}}\,2{{p}^{3}}.\] The element K is expected to show the maximum difference in \[{{\Delta }_{i}}{{H}_{1}}\] and \[{{\Delta }_{i}}{{H}_{2}}\]  values. Actually, when its atom loses one electron; the cation left has the noble gas configuration. The removal of the second electron from the ion requires very high ionization enthalpy \[({{\Delta }_{i}}{{H}_{2}})\].