STANDARDChemistry-Periodic Table
STANDARD Chemistry Lanthanoids MCQ Question
Type: MCQ-conceptual-Medium
The correct order of ionic radii of Ce, La, Pm and Yb in +3 oxidation state is
A
La³⁺ < Pm³⁺ < Ce³⁺ < Yb³⁺
B
Yb³⁺ < Pm³⁺ < Ce³⁺ < La³⁺
C
La³⁺ < Ce³⁺ < Pm³⁺ < Yb³⁺
D
Yb³⁺ < Ce³⁺ < Pm³⁺ < La³⁺
Correct Answer
Option B
Detailed Explanation
The overall decrease in atomic and ionic radii from La³⁺ to Lu³⁺ is called lanthanoid contraction. Hence, the correct order is Yb³⁺ < Pm³⁺ < Ce³⁺ < La³⁺.
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