Question

Which of the following iswhy the atomic radii of the second and third transition series are almost same?

(a) Actinoid contraction

(b) Radioactive nature

(c) Lanthanoid contraction

(d) Filled d-orbital

This question was addressed to me during an online exam.

This key question is from General Properties of the Transition Elements (D-Block) in chapter D and F-Block Elements of Chemistry – Class 12

Answer 1

Right choice is (c) Lanthanoid contraction

The explanation: In the atoms of the second transition series, the number of shells increases and so, their atomic radii is greater than that of the first transition series. The atomic radii of the second and third transition series are almost same due to lanthanoid contraction.