Question

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

• A. 36
• B. 18
• C. 54
• D. 10

Answer 1

The correct option is A 36

First inert gas which contains d-electrons is Kr.
$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^6$

Here in this,
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, which is equal to total number of d-electrons.

So, inert gas is $Kr$, atomic no. 36.