How many unpaired electrons are present in `NO` molecule ?

Answer

To determine the number of unpaired electrons in the nitric oxide (NO) molecule, we can follow these steps:

### Step 1: Determine the total number of electrons in NO
- The atomic number of nitrogen (N) is 7, which means it has 7 electrons.
- The atomic number of oxygen (O) is 8, which means it has 8 electrons.
- Therefore, the total number of electrons in NO is:
\[ 7 \text{ (from N)} + 8 \text{ (from O)} = 15 \text{ electrons} \]

### Step 2: Write the molecular orbital configuration
- According to molecular orbital theory, the electrons in NO are filled into molecular orbitals in the following order:
- \(\sigma_{1s}^2\)
- \(\sigma^*_{1s}^2\)
- \(\sigma_{2s}^2\)
- \(\sigma^*_{2s}^2\)
- \(\sigma_{2p_z}^2\)
- \(\pi_{2p_x}^2\)
- \(\pi_{2p_y}^2\)
- \(\pi^*_{2p_x}^1\) (Here is where we have an unpaired electron)

### Step 3: Identify the unpaired electrons
- From the molecular orbital configuration, we see that:
- The \(\pi^*_{2p_x}\) orbital has 1 electron that is unpaired.
- All other orbitals are either fully filled (paired) or empty.

### Conclusion
- Therefore, the NO molecule has **1 unpaired electron**.

### Summary
The number of unpaired electrons in the NO molecule is **1**.

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