Question

What is meant by lanthanide contraction actinoid contraction is greater than lanthanoid contraction why?

Answer 1

Actinoid contraction is greater from element to element than lanthanoid contraction. The decrease in atomic (or ionic) radii (actinoid contraction) in actinoids is greater than lanthanoid contraction because 5 f -electrons have poor shielding effect as compared to 4f-electrons.