Which of the following has `4f^(7)` configuration

Options

A. Pr
B. Gd
C. Nd
D. Am

Answer

To determine which element has the electron configuration of `4f^7`, we need to analyze the electron configurations of the given options.

### Step-by-Step Solution:

1. **Understand the 4f Series**:
- The 4f series consists of the lanthanide elements, which are elements with atomic numbers 57 (Lanthanum) to 71 (Lutetium). The 4f subshell can hold a maximum of 14 electrons.

2. **List the Options**:
- The options provided are:
- A) Praseodymium (Pr)
- B) Gadolinium (Gd)
- C) Neodymium (Nd)
- D) Americium (Am)

3. **Check Electron Configurations**:
- **Praseodymium (Pr)**:
- Atomic number: 59
- Configuration: [Xe] 4f³ 6s²
- This does not have 4f⁷ configuration.

- **Gadolinium (Gd)**:
- Atomic number: 64
- Configuration: [Xe] 4f⁷ 6s²
- This has 4f⁷ configuration. This is a potential answer.

- **Neodymium (Nd)**:
- Atomic number: 60
- Configuration: [Xe] 4f⁴ 6s²
- This does not have 4f⁷ configuration.

- **Americium (Am)**:
- Atomic number: 95
- Configuration: [Rn] 5f⁷ 7s²
- This does not have 4f⁷ configuration.

4. **Conclusion**:
- The only element that has the `4f^7` configuration is **Gadolinium (Gd)**.

### Final Answer:
**The element with the `4f^7` configuration is Gadolinium (Gd).**

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