Which of the following does not illustrate the anomalous properties of lithium?

Options

A. Li is much softer than the other group first metals
B. The melting point and boiling point of Li are comparatively high
C. Li forms a nitride `Li_3N` unlike group 1 metals
D. The ion of Li and its compound are more heavily hydrated then those of rest of the group 1 elements

Answer

To determine which of the following options does not illustrate the anomalous properties of lithium, we need to analyze each option in relation to the known anomalous properties of lithium compared to other alkali metals (sodium and potassium).

### Step-by-Step Solution:

1. **Understanding Anomalous Properties**:
- Anomalous properties refer to characteristics that are different from those of other elements in the same group. For lithium, these properties arise mainly due to its small size and high charge density.

2. **Analyzing Option A**:
- **Statement**: "Lithium is much softer than other group I metals."
- **Analysis**: This statement is incorrect. Lithium is actually harder than sodium and potassium due to its strong metallic bonding. Therefore, this option does not illustrate an anomalous property of lithium.

3. **Analyzing Option B**:
- **Statement**: "The melting point and the boiling point of lithium are comparatively high."
- **Analysis**: This statement is true. Lithium has a higher melting and boiling point compared to other alkali metals due to its strong metallic bonds.

4. **Analyzing Option C**:
- **Statement**: "Lithium forms a nitride, Li3N, unlike group I metals."
- **Analysis**: This statement is also true. Lithium uniquely forms lithium nitride, while other alkali metals do not form nitrides.

5. **Analyzing Option D**:
- **Statement**: "The ions of lithium and its compounds are more heavily hydrated than those of the rest of group one elements."
- **Analysis**: This statement is true. Due to its small size, lithium ions can be surrounded by more water molecules, leading to higher hydration.

6. **Conclusion**:
- The only statement that does not illustrate the anomalous properties of lithium is **Option A**: "Lithium is much softer than other group I metals." This is incorrect because lithium is harder than sodium and potassium.

### Final Answer:
**Option A: Lithium is much softer than other group I metals.**

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