In group `15` elements, the number of unpaired electrons in valence shell is____.

Options

A. 0
B. 2
C. 3
D. 4

Answer

To determine the number of unpaired electrons in the valence shell of group 15 elements, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Group 15 Elements**:
The elements in group 15 of the periodic table are nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi).

2. **Determine the Valence Shell Configuration**:
- For nitrogen (N), the valence shell is n=2:
- Electronic configuration: 1s² 2s² 2p³
- For phosphorus (P), the valence shell is n=3:
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p³
- For arsenic (As), the valence shell is n=4:
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4p³
- For antimony (Sb), the valence shell is n=5:
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4p⁶ 5s² 5p³
- For bismuth (Bi), the valence shell is n=6:
- Electronic configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4p⁶ 5s² 5p⁶ 6s² 6p³

3. **Count the Unpaired Electrons**:
- In the case of nitrogen (N), the 2p³ configuration means there are three electrons in the p orbitals. According to Hund's rule, these three electrons will occupy separate p orbitals with parallel spins, resulting in 3 unpaired electrons.
- For phosphorus (P), the 3p³ configuration also results in 3 unpaired electrons.
- The same applies to arsenic (As), antimony (Sb), and bismuth (Bi); each will have 3 unpaired electrons in their respective p orbitals.

4. **Conclusion**:
The number of unpaired electrons in the valence shell for all group 15 elements is consistently 3.

### Final Answer:
The number of unpaired electrons in the valence shell of group 15 elements is **3**.

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