question_answer 95)

  Electronic configuration of some elements is given in column I and their electron gain enthalpies are given in column II. Match the electronic configuration with electron gain enthalpy.

Column l Electronic configuration	Column ll Electron gain enthalpy/ \[\mathbf{kJ}\,\mathbf{mo}{{\mathbf{l}}^{\mathbf{-1}}}\]
(1) \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}\]	(a) ? 53
(2) \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{1}}\]	(b) ? 328
(3) \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}2{{p}^{5}}\]	(c) ? 141
(4) \[1{{s}^{2}}2{{s}^{2}}2{{p}^{4}}\]	(d) + 48

               

Answer:

  (i - d) Intert gases \[(2{{n}^{2}}n{{p}^{6}})\] have positive electron gain enthalpy because addition of electron is not easily possible. (ii - a) Alkali metals have very low electron gain enthalpy. (iii - b) Halogens (chlorine) have very large negative electron gain enthalpy. (iv - c) Oxygen has electron gain enthalpy, next to (chlorine) halogens because oxygen is also an electron deficient element.