Q. Arrange $Ce^{3 +},\ La^{3 +},\ Pm^{3 +}$ and $Yb^{3 +}$ in increasing order of their ionic radii
A) $Yb^{3 +} < Pm^{3 +} < Ce^{3 +} < La^{3 +}$
B) $Ce^{3 +} < Yb^{3 +} < Pm^{3 +} < La^{3 +}$
C) $Yb^{3 +} < Pm^{3 +} < La^{3 +} < Ce^{3 +}$
D) $Pm^{3 +} < La^{3 +} < Ce^{3 +} < Yb^{3 +}$
Explanation
(a)
Due to lanthanoid contraction order will be $Yb^{3 +} < Pm^{3 +} < Ce^{3 +} < La^{3 +}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.