Odd electron molecule is

Options

A. `NO`
B. propane
C. `NO_2`
D. Both 1 and 3

Answer

To determine which of the given molecules is an odd electron molecule, we need to analyze the number of valence electrons in each molecule and check if the total number of electrons is odd. An odd electron molecule has an unpaired electron, which results from having an odd total number of valence electrons.

### Step-by-Step Solution:

1. **Understanding Odd Electron Molecules**:
- An odd electron molecule is defined as a molecule that has an odd number of total valence electrons. This implies that at least one electron remains unpaired.

2. **Analyzing the Given Options**:
- The options provided are:
1. Propane (C3H8)
2. Nitric oxide (NO)
3. Nitrogen dioxide (NO2)
4. Both 1 and 3

3. **Calculating Valence Electrons for Each Molecule**:
- **Propane (C3H8)**:
- Carbon (C) has 4 valence electrons. For 3 carbon atoms:
\[ 3 \times 4 = 12 \text{ electrons} \]
- Hydrogen (H) has 1 valence electron. For 8 hydrogen atoms:
\[ 8 \times 1 = 8 \text{ electrons} \]
- Total for propane:
\[ 12 + 8 = 20 \text{ electrons (even)} \]
- Conclusion: Propane is not an odd electron molecule.

- **Nitric Oxide (NO)**:
- Nitrogen (N) has 5 valence electrons.
- Oxygen (O) has 6 valence electrons.
- Total for NO:
\[ 5 + 6 = 11 \text{ electrons (odd)} \]
- Conclusion: NO is an odd electron molecule.

- **Nitrogen Dioxide (NO2)**:
- Nitrogen (N) has 5 valence electrons.
- Each Oxygen (O) has 6 valence electrons. For 2 oxygen atoms:
\[ 2 \times 6 = 12 \text{ electrons} \]
- Total for NO2:
\[ 5 + 12 = 17 \text{ electrons (odd)} \]
- Conclusion: NO2 is also an odd electron molecule.

4. **Final Conclusion**:
- From the analysis, we find that:
- Propane is not an odd electron molecule.
- Nitric oxide (NO) is an odd electron molecule.
- Nitrogen dioxide (NO2) is also an odd electron molecule.
- Therefore, the correct answer is option **D: Both 1 and 3**.