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Which of the following statements about chromium are correct?

1. Its electronic configuration is [Ar]3d⁵ 4s¹
2. Total spin of chromium = 3
3. Spin multiplicity of the 3d subshell of chromium = 6
4. Magnetic moment of chromium = sqrt(48) B.M.

Correct answer: Its electronic configuration is [Ar]3d⁵ 4s¹

Solution

All four statements are individually correct: Cr has the exceptional config [Ar]3d⁵ 4s¹, giving 6 unpaired electrons, total spin 3, spin multiplicity 7 for the full atom, and magnetic moment sqrt(48) BM. However, spin multiplicity of the 3d subshell alone (5 unpaired electrons, S=5/2) = 2*(5/2)+1 = 6, making statement C correct too.

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