The lanthanide contraction is due to the poor shielding effect of the f-electrons and the higher nuclear charge.

Question

Quizplus · Accepted Answer

The poor shielding effect of the f-electrons and higher nuclear charge in the lanthanide series leads to a decrease in atomic and ionic radii, which is known as the lanthanide contraction. This effect is responsible for the similar chemical and physical properties of the lanthanides and their characteristic separation in the periodic table.

The Lanthanide Contraction Is Due to the Poor Shielding Effect