How would you account for the following : Actinoid contraction is greater than lanthanoid contraction.
Actinoid contraction is greater from element to element than lanthanoid contraction. Why?
In actinoids, 5 f-orbitals are filled. These 5 f-orbitals have a poorer shielding effect than 4 f-orbitals (in lanthanoids). Thus, the effective nuclear charge experienced by electrons in valence shells in case of actinoids is much more than that experienced by electrons in valence shells in case of lanthanoids. Hence, the size contraction in actinoids is greater than that in lanthanoids.