Electronic configuration of species `M^(2+)` is `1s^(2) 2s^(2) 2p^(6) 3s^(6) 3d^(6)`and its atomic weight is 56. The number of neutrons in the nucleus of species M is

Options

A. 26
B. 22
C. 30
D. 24

Answer

C

Explanation

`M^(2+) : 1s^2 2s^2 2p^6 3s^2 3s^6`
`M : 1s^2 s^2 2p^6 3s^2 3s^8`
Atomic number = 26
Mass number = 56
No. of neutrons = 56 - 26 = 30.