One among the following set of quantum numbers defines the highest energy electron in scandium (I)ion

Options

A. n=3, l=1, m=0, s= -1/2
B. n=3, l=0, m=0, s= -1/2
C. n=4, l=0, m=0, s= +1/2
D. n=3, l=2, m=2, s= +1/2

Answer

C

Explanation

`._21 Se^+` ion has conf. =`Is^2 2s^2 2p^6 3s^2 3p^6 3d^1 4s^1`
Highest energy electron is 4s
During ionization such electron is removed first from 4s-orbital only. Although 3d-is filled after 4s