Which alkaline earth metal compound is volatile

Options

A. `Be_(3)N_(2)`
B. `Mg_(3)N_(2)`
C. `Ca_(3)N_(2)`
D. None

Explanation

To determine which alkaline earth metal compound is volatile, we need to analyze the properties of the given compounds: beryllium nitrite, magnesium nitrite, and calcium nitrite.

### Step-by-Step Solution:

1. **Identify the Compounds**: The question lists three compounds: beryllium nitrite (Be(NO2)2), magnesium nitrite (Mg(NO2)2), and calcium nitrite (Ca(NO2)2). All of these are nitrites of alkaline earth metals.

2. **Understand Alkaline Earth Metals**: Alkaline earth metals belong to Group 2 of the periodic table, which includes beryllium (Be), magnesium (Mg), calcium (Ca), and others.

3. **Analyze Beryllium**: Beryllium is known to exhibit anomalous behavior compared to other alkaline earth metals. This is due to its small atomic size and high electronegativity, which allows it to form covalent compounds.

4. **Covalent vs. Ionic Nature**:
- Beryllium nitrite (Be(NO2)2) is covalent in nature due to beryllium's small size and high electronegativity.
- Magnesium nitrite (Mg(NO2)2) and calcium nitrite (Ca(NO2)2) are ionic compounds. Ionic compounds typically have higher melting and boiling points due to the strong ionic bonds.

5. **Volatility Consideration**: Volatile compounds tend to have lower boiling points. Since beryllium nitrite is covalent, it has a lower boiling point compared to the ionic magnesium and calcium nitrites, which are less volatile.

6. **Conclusion**: Based on the analysis, the compound that is volatile among the options provided is beryllium nitrite (Be(NO2)2).

### Final Answer:
The volatile alkaline earth metal compound is **beryllium nitrite (Be(NO2)2)**.

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