Which of the following does not have abnormal electronic configuration ?

Options

A. Cr
B. Pd
C. Pt
D. Hg

Answer

To determine which of the following elements does not have an abnormal electronic configuration, we will analyze the electronic configurations of each element mentioned in the video transcript.

### Step-by-Step Solution:

1. **Understand Abnormal Electronic Configuration**:
- Abnormal electronic configurations occur when the actual electron configuration of an element differs from the expected configuration based on the Aufbau principle.

2. **Analyze Chromium (Cr)**:
- Atomic Number: 24
- Expected Configuration: Argon (Ar) 3d^4 4s^2
- Actual Configuration: Argon (Ar) 3d^5 4s^1
- Conclusion: Chromium has an abnormal electronic configuration.

3. **Analyze Palladium (Pd)**:
- Atomic Number: 46
- Expected Configuration: Krypton (Kr) 4d^8 5s^2
- Actual Configuration: Krypton (Kr) 4d^10 5s^0
- Conclusion: Palladium has an abnormal electronic configuration.

4. **Analyze Platinum (Pt)**:
- Atomic Number: 78
- Expected Configuration: Xenon (Xe) 4f^14 5d^8 6s^2
- Actual Configuration: Xenon (Xe) 4f^14 5d^9 6s^1
- Conclusion: Platinum has an abnormal electronic configuration.

5. **Analyze Mercury (Hg)**:
- Atomic Number: 80
- Expected Configuration: Xenon (Xe) 4f^14 5d^10 6s^2
- Actual Configuration: Xenon (Xe) 4f^14 5d^10 6s^2
- Conclusion: Mercury has a normal electronic configuration.

6. **Final Conclusion**:
- Among the elements analyzed, only Mercury (Hg) does not have an abnormal electronic configuration.

### Answer:
The element that does not have an abnormal electronic configuration is **Mercury (Hg)**.