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Question 860009
JEE Chemistry · Hard

d- and f-Block Elements: JEE Advanced MCQ

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JEE AdvancedHardQuestion 860009

Question

Among 3d transition metals, the one with the highest number of unpaired electrons is:
  1. A
    Cr (3d⁵4s¹, 6 unpaired total)
    Correct
  2. B
    Mn (3d⁵4s², 5 unpaired in d)
  3. C
    Fe (3d⁶4s², 4 unpaired)
  4. D
    Cu (3d¹⁰4s¹, 1 unpaired)

Correct answer

Cr (3d⁵4s¹, 6 unpaired total)

Explanation

Cr: [Ar]3d⁵4s¹ → 5 unpaired in 3d + 1 in 4s = 6 total unpaired electrons. Mn has 5d + 2s electrons but the 4s are paired → 5 unpaired. So Cr has most unpaired e⁻ among 3d metals.

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