Q. Which of the following has got incompletely filled $f$-subshell?
A) Gadolinium
B) Lutetium
C) Lawrencium
D) Tantalum
Explanation
(a)
Gadolinium (Z=64) [Xe] $4f^{7},5d^{1},6s^{2}$
Lutetium(Z=71)[Xe] $4f^{14},5d^{1},6s^{2}$
Lawrencium(Z=103)[Rn] $5f^{14},6d^{1},7s^{2}$
Tantalum(Z=73) [Xe]$4f^{14},5d^{3},6s^{2}$
Hence, gadolinium has got incompletely filled $f$-subshell.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.