NEET Solved Paper 2014 Question 30
Question: Reason of lanthanoid contraction is [AIPMT 2014]
Options:
A) negligible screening effect of T orbitals
B) increasing nuclear charge
C) decreasing nuclear charge
D) decreasing screening effect
Show Answer
Answer:
Correct Answer: A
Solution:
- Lanthanoid contraction is the regular decrease in atomic and ionic radii of lanthanides. This is due to the imperfect shielding [or poor screening effect] of f-orbitals due to their diffused shape, which unable to counterbalance the effect of the increased nuclear charge. Hence, the net result is a contraction in size of lanthanoids.
