Give the name and atomic number of the inert gas atom in which the total number of `d`-electrons is equal to the difference in number to the `p`-and `-s`-electrons.

Explanation

The first inert gas which contains `d`-electrons is in `4th` period (or from `3d` transition element seris), i.e., `Kr(Z = 36)`.
Electronic configuration of `Kr`:
`1s^(2), 2s^(2)2p^(6),3s^(2)3p^(6) 3d^(10), 4s^(2)4p^(6)`.
Total number of `d`-electrons `= 10`
Total number of `p`-electrons `= 6+6+6 =18`
Total number of `s` -electrons `= 2+2+2+2 = 8`
Difference in total number of `p`-and `-s`-electrons `= (18-8) = 10`
Thus, the inert gas is `Kr` (krypton).