# Which of the following configuration is expected to have max different in second and third ionization energy :

$(a)\;(1S)^2(2S)^2(2P)^2 \\(b)\;(1S)^2(2S)^2(2P)^6 \\ (c)\;(1S)^2(2S)^2(2P)^6(3S)^2 \\ (d)\;(1S)^2(2S)^2(2P)^1$

The configuration $(1S)^2(2S)^2(2P)^6(3S)^2$ will have maximum difference in second and third ionization energies.
Hence c is the correct answer.
Second ionization implies removal of 3s electron and third ionization implies removal of electron from stable configuration of noble gas .
edited Oct 26, 2017 by meena.p