Electronic Configuration
The electronic configuration of chromium (Z = 24) is:
Select the correct option:
Solution
[Ar] 3d⁵ 4s¹
Expected configuration using Aufbau principle for Z=24 is [Ar]3d44s2. However, Chromium (Cr) and Copper (Cu) show anomalous configurations due to the extra stability of half-filled and completely filled subshells.
- In Cr, an electron from the 4s orbital jumps to the 3d orbital to make 3d5 (exactly half-filled) and 4s1 (exactly half-filled).
- Correct configuration: [Ar]3d54s1.
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More electronic configuration Practice Questions
Among the following species, which one has the electronic configuration [Ar] 3d5?
Among the following species, which one has the electronic configuration [Ar] 3d5?
Which of the following electronic configurations violates Hund's rule of maximum multiplicity?
Which of the following electronic configurations violates Hund's rule of maximum multiplicity?
The number of unpaired electrons in Fe²⁺ (Z = 26) is:
The number of unpaired electrons in Fe²⁺ (Z = 26) is:
About This Question
- Subject
- chemistry
- Chapter
- atomic structure
- Topic
- electronic configuration
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
[Ar] 3d⁵ 4s¹
Expected configuration using Aufbau principle for Z=24 is [Ar]3d44s2. However, Chromium (Cr) and Copper (Cu) show anomalous configurations due to the extra stability of half-filled and completely filled subshells.
- In Cr, an electron from the 4s orbital jumps to the 3d orbital to make 3d5 (exactly half-filled) and 4s1 (exactly half-filled).
- Correct configuration: [Ar]3d54s1.
This medium difficulty chemistry question is from the chapter atomic structure, covering the topic of electronic configuration. It appeared in the 2025 exam.
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