The D And F Block Elements Ques 78
78. Reason of lanthanoid contraction is:-
[2014]
(a) Negligible screening effect of ’ $f$ ’ orbitals
(b) Increasing nuclear charge
(c) Decreasing nuclear charge
(d) Decreasing screening effect
Show Answer
Solution:
- (a) The shape of $f$-orbitals is very much diffused and they have poor shielding effect.
The effective nuclear charge increases due to imperfect shielding of one electron by another in the same subshell which causes the contraction in the size of electron charge cloud. This contraction in size is known as lanthanoid contraction.
BETA
