Q. Reason of lanthanoid contraction is :
A) Negligible screening effect of 'f' orbitals
B) Increasing nuclear charge
C) Decreasing nuclear charge
D) Decreasing screening effect
Explanation
[Solution] The 4f electrons shield the outer electrons very poorly, so the rising nuclear charge pulls them in. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.