Which of the following is d-block element?

Options

A. Si
B. Hg
C. Mg
D. Al

Answer

To determine which of the given elements is a d-block element, we need to analyze the electronic configurations of each element and identify the block they belong to based on the orbital in which their last electron resides.

### Step-by-Step Solution:

1. **Identify the Elements**: The elements provided are silicon, mercury, magnesium, and aluminum.

2. **Determine the Atomic Number and Electronic Configuration**:
- **Silicon (Si)**: Atomic number = 14
- Electronic configuration: \( \text{Ne} \, 3s^2 \, 3p^2 \)
- **Mercury (Hg)**: Atomic number = 80
- Electronic configuration: \( \text{Xe} \, 6s^2 \, 4f^{14} \, 5d^{10} \)
- **Magnesium (Mg)**: Atomic number = 12
- Electronic configuration: \( \text{Ne} \, 3s^2 \)
- **Aluminum (Al)**: Atomic number = 13
- Electronic configuration: \( \text{Ne} \, 3s^2 \, 3p^1 \)

3. **Identify the Block for Each Element**:
- **Silicon**: The last electron is in the p orbital (3p), so it is a **p-block element**.
- **Mercury**: The last electron is in the d orbital (5d), so it is a **d-block element**.
- **Magnesium**: The last electron is in the s orbital (3s), so it is an **s-block element**.
- **Aluminum**: The last electron is in the p orbital (3p), so it is a **p-block element**.

4. **Conclusion**: Among the given elements, the only d-block element is **Mercury (Hg)**.

### Final Answer:
The d-block element among the given options is **Mercury (Hg)**.

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