JEE Main 2023 — D And F Block Elements Question with Solution
From: JEE Main 2023 (Online) 13th April Morning Shift
Question
The pair of lanthanides in which both elements have high third - ionization energy is :
Choose an option
Show full solutionCorrect option: C
Correct answer
CEu, Yb
Step-by-step explanation
1. Eu²⁺: [Xe] 4f⁷
2. Yb²⁺: [Xe] 4f¹⁴
Eu²⁺ has a half-filled 4f orbital, while Yb²⁺ has a fully-filled 4f orbital. Both of these configurations lead to increased stability due to the symmetrical distribution of electrons in the 4f subshell, resulting in higher ionization energies for both Europium (Eu) and Ytterbium (Yb).
Thus, the correct answer is Eu (Europium) and Yb (Ytterbium), as both elements have high third ionization energies due to their half-filled and fully-filled 4f subshell configurations in their divalent cation forms.
2. Yb²⁺: [Xe] 4f¹⁴
Eu²⁺ has a half-filled 4f orbital, while Yb²⁺ has a fully-filled 4f orbital. Both of these configurations lead to increased stability due to the symmetrical distribution of electrons in the 4f subshell, resulting in higher ionization energies for both Europium (Eu) and Ytterbium (Yb).
Thus, the correct answer is Eu (Europium) and Yb (Ytterbium), as both elements have high third ionization energies due to their half-filled and fully-filled 4f subshell configurations in their divalent cation forms.
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This is a previous-year question from JEE Main 2023, covering the D And F Block Elements chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.