Which of these materials lacks hardness?

Options

A. Gold
B. Lithium
C. Copper
D. Diamond

Answer

To determine which of the given materials lacks hardness, we will analyze each option step by step.

### Step 1: Identify the materials
The materials we need to evaluate are:
- Gold
- Lithium
- Copper
- Diamond

### Step 2: Analyze the hardness of each material
1. **Diamond**:
- Diamond is known to be one of the hardest substances on Earth. It is often used in cutting tools and jewelry due to its exceptional hardness.
- **Conclusion**: Diamond is not the answer.

2. **Gold**:
- Gold is a metal that is relatively hard and malleable. It can be hammered into thin sheets and is resistant to corrosion.
- **Conclusion**: Gold is not the answer.

3. **Copper**:
- Copper is also a metal that is known for its good conductivity and moderate hardness. While it is softer than gold and diamond, it is still considered a hard material compared to many others.
- **Conclusion**: Copper is not the answer.

4. **Lithium**:
- Lithium is an alkali metal, which is known for being very soft. It can be easily cut with a knife and has a low melting point compared to the other materials listed.
- **Conclusion**: Lithium is the least hard among the options.

### Step 3: Final conclusion
Based on the analysis, the material that lacks hardness is **lithium**.