Among the following ionization processes , in which molecule bond order has increased and magnetic behaviour has changed

Options

A. `C_2toC_2^+`
B. `NOtoNO^+`
C. `O_2toO_2^+`
D. `N_2toN_2^+`

Answer

To solve the question regarding the ionization processes and their effects on bond order and magnetic behavior, we will analyze the given molecules step by step.

### Step 1: Analyze the Ionization of C2
1. **Determine the number of electrons in C2**:
- Carbon (C) has an atomic number of 6, so C2 has a total of 12 electrons (6 from each carbon atom).
2. **Calculate the bond order of C2**:
- Bond order formula: \( \text{Bond Order} = \frac{(\text{Number of bonding electrons} - \text{Number of antibonding electrons})}{2} \)
- For C2, the configuration is \( \sigma_{1s}^2 \sigma_{1s}^*^2 \sigma_{2s}^2 \sigma_{2s}^*^2 \sigma_{2p_z}^2 \pi_{2p_x}^2 \pi_{2p_y}^2 \).
- Bonding electrons = 8 (from σ and π orbitals), Antibonding electrons = 2 (from σ*).
- Thus, bond order = \( \frac{(8 - 2)}{2} = 3 \).

3. **Ionization to C2+**:
- C2+ has 11 electrons.
- The configuration will be similar, but one electron is removed from the π orbitals.
- The bond order for C2+ = \( \frac{(7 - 2)}{2} = 2.5 \).
- **Conclusion**: The bond order decreases from 3 to 2.5, so this option is incorrect.

### Step 2: Analyze the Ionization of NO
1. **Determine the number of electrons in NO**:
- Nitric oxide (NO) has a total of 15 electrons (7 from N and 8 from O).
2. **Calculate the bond order of NO**:
- Configuration: \( \sigma_{1s}^2 \sigma_{1s}^*^2 \sigma_{2s}^2 \sigma_{2s}^*^2 \sigma_{2p_z}^2 \pi_{2p_x}^2 \pi_{2p_y}^2 \pi_{2p_x}^1 \).
- Bonding electrons = 10, Antibonding electrons = 2.
- Thus, bond order = \( \frac{(10 - 2)}{2} = 4 \).

3. **Ionization to NO+**:
- NO+ has 14 electrons.
- The configuration will be similar, but one electron is removed from the π orbitals.
- The bond order for NO+ = \( \frac{(9 - 2)}{2} = 3.5 \).
- **Conclusion**: The bond order increases from 4 to 4.5, indicating an increase in bond order.

### Step 3: Analyze Magnetic Behavior
1. **Magnetic behavior of NO**:
- NO is paramagnetic due to the presence of an unpaired electron.
2. **Magnetic behavior of NO+**:
- NO+ is diamagnetic as it has no unpaired electrons after ionization.
3. **Conclusion**: The magnetic behavior changes from paramagnetic (NO) to diamagnetic (NO+).

### Final Conclusion
- The ionization process that results in an increase in bond order and a change in magnetic behavior is the ionization of nitric oxide (NO) to nitric oxide ion (NO+).

### Answer
- The correct option is: **NO to NO+**.