Arrange the following atomic numbers in the increasing order of number of unpaired electrons

Options

A. 16
B. 32
C. 40
D. 57

Explanation

Electronic configuration is ` 1s^2 2s^2 2p^6 3s^2 3p^4` number of unpaired electrons is 2.
Electronic configuration is Electronic configuration is ` 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^2`number of unpaired electrons is 2.
Electronic configuration is ` 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^2` number of unpaired electrons is 2.
Electronic configuration is `[Xe] 6s^2 5d^1` number of unpaired electrons 1
`therefore` order is (i) = (ii)= (iii) gt (iv)