General electronic configuration of actinoids is `(n-2)f^(1-14)(n-1)d^(0-2)ns^(2)`. Which of the following actinoids have one electron in 6d orbital?

Options

A. U (Atomic number. 92)
B. Np (Atomic number. 93)
C. Pu (Atomic number. 94)
D. Am (Atomic number. 95)

Explanation

To determine which actinoids have one electron in the 6d orbital, we will analyze the electronic configurations of the given actinoids: uranium (U), neptunium (Np), plutonium (Pu), and americium (Am).

### Step-by-Step Solution:

1. **Understand the General Electronic Configuration**:
The general electronic configuration of actinoids is given as \[(n-2)f^{1-14}(n-1)d^{0-2}ns^{2}\]. For actinoids, \(n\) is 7, so the configuration can be specified as:
\[ 5f^{1-14} 6d^{0-2} 7s^{2} \]

2. **Identify the Atomic Numbers**:
- Uranium (U) has atomic number 92.
- Neptunium (Np) has atomic number 93.
- Plutonium (Pu) has atomic number 94.
- Americium (Am) has atomic number 95.

3. **Write the Electronic Configurations**:
- **Uranium (U)**:
- Configuration: \( [Rn] 5f^3 6d^1 7s^2 \)
- **Neptunium (Np)**:
- Configuration: \( [Rn] 5f^4 6d^1 7s^2 \)
- **Plutonium (Pu)**:
- Configuration: \( [Rn] 5f^6 6d^0 7s^2 \)
- **Americium (Am)**:
- Configuration: \( [Rn] 5f^7 6d^0 7s^2 \)

4. **Analyze the 6d Orbital**:
- For **Uranium (U)**: 6d has 1 electron.
- For **Neptunium (Np)**: 6d has 1 electron.
- For **Plutonium (Pu)**: 6d has 0 electrons.
- For **Americium (Am)**: 6d has 0 electrons.

5. **Conclusion**:
The actinoids that have one electron in the 6d orbital are **Uranium (U)** and **Neptunium (Np)**.

### Final Answer:
The actinoids that have one electron in the 6d orbital are **1. Uranium (U) and 2. Neptunium (Np)**.

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