which of the following configurations represents atoms of the elements having the higest second ionisation energy?

Options

A. ` 1s^(2) 2 s^(2) 2p^(4)`
B. `1 s^(2) 2s^(2) 2p^(6)`
C. `1 s^(2) 2s^(2) 2p^(6) 3s^(1)`
D. `1s^(2) 2s^(2) 2p^(6) 3s^(2)`

Answer

C

Explanation

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