Question

Which of the following configurations represents atoms of the elements having the highest second ionization energy?

• A. $1s^{2}2s^{2}2p^{6}3s^2$
• B. $1s^{2}2s^{2}2p^6$
• C. $1s^{2}2s^{2}2p^4$
• D. $1s^{2}2s^{2}2p^{6}3s^1$

Answer 1

The correct option is D $1s^{2}2s^{2}2p^{6}3s^1$

Element which has one electron in the valence shell has highest second ionization energy because in this case $2^{nd}$ electron has to be lost from the inert gas core.
Thus, option (c) is correct answer.