Q. What is the atomic number of the element with $M^{2 +}$ ion having electronic configuration $\lbrack Ar\rbrack 3d^{8}$?
A) 25
B) 28
C) 27
D) 26
Explanation
(b)
E.C. of $M$ $= \lbrack Ar\rbrack 4s^{2}3d^{8}$
E.C. of $M^{2 +} = \lbrack Ar\rbrack 4s^{0}3d^{8}$
Total electrons =28=atomic number
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.