JEE Main 2024 · 27 January · evening · Single correct · +4 / −1

Choose the correct option having all the elements with d¹⁰ electronic configuration from the following :

  1. (a) ⁴⁶ Pd, ²⁸ Ni, ²⁶ Fe, ²⁴ Cr
  2. (b) ²⁹ Cu, ³⁰ Zn, ⁴⁸ Cd, ⁴⁷ Ag
  3. (c) ²⁷ Co, ²⁸ Ni, ²⁶ Fe, ²⁴ Cr
  4. (d) ²⁸ Ni, ²⁴ Cr, ²⁶ Fe, ²⁹ Cu
Answer and solution

Answer (b) ²⁹ Cu, ³⁰ Zn, ⁴⁸ Cd, ⁴⁷ Ag

Solution

Chemistry ma’am · 3 steps

Write the d-subshell for each atom, and remember Cu and Ag borrow an s electron to fill d.

  1. What to check. A d¹⁰ element has a completely filled (n-1)d subshell in its ground-state atom. Write the outer configuration of every element and look only at the d count.
  2. Two exceptions. Copper and silver take (n-1)d¹⁰ ns¹, not d⁹s², because a full d subshell is extra stable. Chromium does the same for a half-filled shell: 3d⁵ 4s¹.
    OptionOuter configurationsAll d¹⁰?
    (a)Pd 4d¹⁰5s⁰, Ni 3d⁸ 4s², Fe 3d⁶ 4s², Cr 3d⁵ 4s¹No, only Pd
    (b)Cu 3d¹⁰4s¹, Zn 3d¹⁰4s², Cd 4d¹⁰5s², Ag 4d¹⁰5s¹Yes, all four
    (c)Co 3d⁷ 4s², Ni 3d⁸ 4s², Fe 3d⁶ 4s², Cr 3d⁵ 4s¹No, none
    (d)Ni 3d⁸ 4s², Cr 3d⁵ 4s¹, Fe 3d⁶ 4s², Cu 3d¹⁰4s¹No, only Cu
  3. So. Only option (b) has every element with a full d subshell: Cu, Zn, Cd and Ag are all d¹⁰.

The idea to keep. Group 11 (Cu, Ag) and group 12 (Zn, Cd) atoms are all d¹⁰. Pd is the odd one out in group 10: 4d¹⁰5s⁰, while Ni stays 3d⁸ 4s².

Answer from the NTA final answer key. Solution by PrepWiser.

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Asked about 170 times in JEE Main since 2020. This question is from 2024.