Q. Which of the following is not a member of $3d$-transition series?
A) $Fe$
B) $Co$
C) $Au$
D) $Cu$
Explanation
(c)
Au is a number of $5d$-series. Fe, Co and Cu all are the members of $3d$-series.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.