All metals are solids except________.

Options

A. Sodium
B. Calcium
C. Mercury
D. Hydrogen

Answer

To solve the question "All metals are solids except________," we will analyze the options provided and identify which metal is not solid at room temperature.

### Step-by-Step Solution:

1. **Understanding the Question**: The question states that all metals are solids except for one. We need to identify which of the given options is not a solid at room temperature.

2. **Reviewing the Options**: The options provided are:
- A) Sodium
- B) Calcium
- C) Mercury
- D) Hydrogen

3. **Analyzing Each Option**:
- **Sodium (Na)**: Sodium is a metal and is solid at room temperature.
- **Calcium (Ca)**: Calcium is also a metal and is solid at room temperature.
- **Mercury (Hg)**: Mercury is a metal, but it is unique because it is liquid at room temperature.
- **Hydrogen (H)**: Hydrogen is a non-metal and is a gas at room temperature.

4. **Identifying the Exception**: Among the options, only mercury is a metal that is not solid at room temperature. Its melting point is -38.83°C, which is below room temperature, causing it to remain in liquid form.

5. **Conclusion**: Therefore, the answer to the question is C) Mercury.

### Final Answer:
All metals are solids except **C) Mercury**.

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