Which of the following does not have valence electron in 3d-series ?

Options

A. Fe(III)
B. Cr(I)
C. Mn(II)
D. P(0)

Answer

To determine which of the given elements does not have valence electrons in the 3d series, we will analyze the electronic configurations of each element mentioned in the question.

### Step-by-Step Solution:

1. **Identify the Elements**: The elements we need to analyze are Iron (Fe), Chromium (Cr), Manganese (Mn), and Phosphorus (P).

2. **Find the Atomic Numbers**:
- Iron (Fe) has an atomic number of 26.
- Chromium (Cr) has an atomic number of 25.
- Manganese (Mn) has an atomic number of 24.
- Phosphorus (P) has an atomic number of 15.

3. **Write the Electronic Configurations**:
- **Iron (Fe)**:
- Electronic configuration: \( \text{[Ar]} \, 4s^2 \, 3d^6 \)
- **Chromium (Cr)**:
- Electronic configuration: \( \text{[Ar]} \, 4s^1 \, 3d^5 \)
- **Manganese (Mn)**:
- Electronic configuration: \( \text{[Ar]} \, 4s^2 \, 3d^5 \)
- **Phosphorus (P)**:
- Electronic configuration: \( \text{[Ne]} \, 3s^2 \, 3p^3 \)

4. **Identify Valence Electrons in 3d Series**:
- For Iron (Fe), the valence electrons in the 3d series are 6 (from 3d^6).
- For Chromium (Cr), the valence electrons in the 3d series are 5 (from 3d^5).
- For Manganese (Mn), the valence electrons in the 3d series are 5 (from 3d^5).
- For Phosphorus (P), there are no 3d electrons present since its configuration ends at 3p.

5. **Conclusion**:
- Among the elements analyzed, **Phosphorus (P)** does not have any valence electrons in the 3d series, as it does not contain any d orbital electrons.

### Final Answer:
**Phosphorus (P)** does not have valence electrons in the 3d series.

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