What is Lanthanoid Contraction. Explain the Cause of Lanthanoid Contraction

Answer: The Lanthanide Contraction refers to the Lanthanide series’ atomic radius trend. Another aspect of the Lanthanide Contraction is that the 5s and 5p orbitals pierce the 4f sub-shell, exposing the 4f orbital to the rising nuclear change, causing the atomic radius to shrink. Throughout the series, this shrinking in size is maintained.

A poor shielding effect of the 4f electrons cause the Lanthanide Contraction. The shielding effect is the phenomenon whereby inner-shell electrons buffer outer-shell electrons from nuclear charge.