Refers to a group of 15 chemical elements in the periodic table with atomic numbers from 57 to 71.

Describes a periodic trend affecting the lanthanoid elements, where the atomic radius decreases with increasing atomic number.

लैंथेनॉइड संकुचन (Lanthanoid Contraction)

English Usage: The lanthanoid contraction leads to a decrease in ionic radii as we move across the series.

Hindi Usage: लैंथेनॉइड संकुचन के कारण श्रृंखला में आगे बढ़ने पर आयनिक त्रिज्या में कमी आती है।