Which of the following is/are paramagnetic:
`NO_(2)`, NO, `N_(2)O_(4)`, `N_(2)O_(2)`, `N_(2)O_(5)`

Options

A. Only `NO_(2)`
B. `NO_(2)`, NO
C. NO, `NO_(2)`, `N_(2)O_(5)`
D. all are paramagnetic

Answer

To determine which of the given compounds are paramagnetic, we need to analyze the number of unpaired electrons in each compound. A species is considered paramagnetic if it has unpaired electrons, while it is diamagnetic if all electrons are paired.

### Step-by-Step Solution:

1. **Identify the compounds and their electron counts:**
- NO₂
- NO
- N₂O₄
- N₂O₂
- N₂O₅

2. **Calculate the total number of electrons for each compound:**
- **For NO₂:**
- Nitrogen (N) has 7 electrons.
- Oxygen (O) has 8 electrons, and there are 2 oxygen atoms.
- Total = 7 (N) + 2 × 8 (O) = 7 + 16 = 23 electrons.

- **For NO:**
- Nitrogen (N) has 7 electrons.
- Oxygen (O) has 8 electrons.
- Total = 7 (N) + 8 (O) = 15 electrons.

- **For N₂O₄:**
- Nitrogen (N) has 7 electrons, and there are 2 nitrogen atoms.
- Oxygen (O) has 8 electrons, and there are 4 oxygen atoms.
- Total = 2 × 7 (N) + 4 × 8 (O) = 14 + 32 = 46 electrons.

- **For N₂O₂:**
- Nitrogen (N) has 7 electrons, and there are 2 nitrogen atoms.
- Oxygen (O) has 8 electrons, and there are 2 oxygen atoms.
- Total = 2 × 7 (N) + 2 × 8 (O) = 14 + 16 = 30 electrons.

- **For N₂O₅:**
- Nitrogen (N) has 7 electrons, and there are 2 nitrogen atoms.
- Oxygen (O) has 8 electrons, and there are 5 oxygen atoms.
- Total = 2 × 7 (N) + 5 × 8 (O) = 14 + 40 = 54 electrons.

3. **Determine the presence of unpaired electrons:**
- **NO₂ (23 electrons):** Odd number of electrons, likely has unpaired electrons → **Paramagnetic.**
- **NO (15 electrons):** Odd number of electrons, likely has unpaired electrons → **Paramagnetic.**
- **N₂O₄ (46 electrons):** Even number of electrons, all paired → **Diamagnetic.**
- **N₂O₂ (30 electrons):** Even number of electrons, all paired → **Diamagnetic.**
- **N₂O₅ (54 electrons):** Even number of electrons, all paired → **Diamagnetic.**

4. **Conclusion:**
- The compounds that are paramagnetic are **NO₂** and **NO**.

### Final Answer:
The paramagnetic compounds are **NO₂ and NO**.

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