Question

The inert gas atom in which the total number of d-electrons is equal to the difference in numbers of total $p-$ and $s-$electrons, is:

• A. $He$
• B. $Ne$
• C. $Ar$
• D. $Kr$

Answer 1

The correct option is D $Kr$

$He,Ne$ and $Ar$ do not have any $d$ electrons, while the difference of their $s$ and $p$ electrons is not zero.

The electronic configuration of krypton (atomic number is 36) is: $1s^2,2s^2,2p^6,3s^2,3p^6,3d^{10},4s^2,4p^6$.

Total $s-$electrons are 8 and total $p-$electrons are 18.

Thus, the difference is 10 and total d-electrons are 10 which are equal.

So, option $D$ is correct answer.