The value of four quantum number for the last electron of atom of element 'X' are n=7, l=1,m=+1 and s=+1/2 or -1/2 and vlaue of spin magnetic momentum for element 'X' is zero element 'X' has two isotopes (I) `""_(Z)^(A)X and ` (II) `""_(Z)^(B)X`.
Q. The possible value of all four quantum numbers for 90th electron of atom of element 'X' is:

Options

A. `{:(n,l,m,s),(6,2,0,-1//2):}`
B. `{:(n,l,m,s),(5,2,-1,+1//2):}`
C. `{:(n,l,m,s),(6,0,0,+1//2):}`
D. `{:(n,l,m,s),(5,3,-2,-1//2):}`

Answer

D

Explanation

90th `e^(-)` goes to 5f subshell to possible four quantum number are 5,3,-2 and -1/2 or +1/2.