General configuration of outermost and penultimate shell is `(n - 1) s^(2) (n - 1) p^(6) (n - 1)d^(x) ns^(2)`. If `n = 4` and `x = 5` then no. of protons in the nucleus will be

Options

A. `gt 25`
B. `lt 24`
C. 25
D. 30

Answer

C

Explanation

Given `n = 4 x = 5`
So `underset(3 s^(2))(4 - 1) s^(2) underset(3 p^(6))(4 - 1) p^(6) underset(3 d^(5))(4 - )d^(5) underset(4 s^(2))4 s^(2)`
Total electron `= 2 + 6 + 2 = 15`
Electron in `1 + 2` orbit `= 2 + 8 = 10`
Total electron `= 10 + 15 = 25`
No. of electron = No. proton
So total proton = 25