The value of four quantum number for the last `e^(-)` of atom of element x are n = 7, l = 1, m = + 1 and `s = +1//2` (or) -`1//2` and value of spin magnetic momentum for element 'X' is zero. Element X has two isotopes `(I)_(z)X^(A) (II)._(z)X^(B)` Given `B-A=18` and B-2Z = 18 where A and B are atomic masses and Z is atomic number.
The correct statment regarding element ''X'' is :

Options

A. Element belong to `18^(th)` group
B. X is inner transition element
C. X is transition element
D. X is representative element

Answer

A

Explanation

Given for element X
n = 7, l = 1, m = + 1 and s = + 1/2 or - 1/2 and `mu=0` (spin only magnetic moment)
7P sub-shell, given `mu=0` then number of unpaired electrons is zero hence it will be `7p^(6)`
X belong to 18 group and `7^(th)` period hence Z = 118
X is p-block element