Which molecule/ion out of the following does not contain unpaired electrons?

Options

A. `N_(2)^(+)`
B. `O_(2)`
C. `O_(2)^(2-)`
D. `B_(2)`

Explanation

To determine which molecule or ion does not contain unpaired electrons, we will analyze the electronic configurations of the given species. Let's go through the analysis step by step.

### Step 1: Identify the total number of electrons for each species.
- **N2+**: Nitrogen (N) has 7 electrons, so N2 has 14 electrons. Losing one electron for N2+ gives us 13 electrons.
- **O2**: Oxygen (O) has 8 electrons, so O2 has 16 electrons.
- **O2^2-**: Gaining 2 electrons for O2^2- gives us 18 electrons.
- **B2**: Boron (B) has 5 electrons, so B2 has 10 electrons.

### Step 2: Write the electronic configurations for each species.
1. **N2+ (13 electrons)**:
- Configuration: σ1s² σ*1s² σ2s² σ*2s² π2p_x² = π2p_y² σ2p_z¹
- Unpaired Electrons: 1 (σ2p_z¹)

2. **O2 (16 electrons)**:
- Configuration: σ1s² σ*1s² σ2s² σ*2s² σ2p_z² π2p_x² = π2p_y² π2p_x¹ π2p_y¹
- Unpaired Electrons: 2 (π2p_x¹ and π2p_y¹)

3. **O2^2- (18 electrons)**:
- Configuration: σ1s² σ*1s² σ2s² σ*2s² σ2p_z² π2p_x² = π2p_y² π*2p_x² = π*2p_y²
- Unpaired Electrons: 0 (all electrons are paired)

4. **B2 (10 electrons)**:
- Configuration: σ1s² σ*1s² σ2s² σ*2s² π2p_x¹ = π2p_y¹
- Unpaired Electrons: 2 (π2p_x¹ and π2p_y¹)

### Step 3: Determine which species has no unpaired electrons.
From the electronic configurations:
- **N2+** has 1 unpaired electron.
- **O2** has 2 unpaired electrons.
- **O2^2-** has 0 unpaired electrons (all paired).
- **B2** has 2 unpaired electrons.

### Conclusion:
The molecule/ion that does not contain unpaired electrons is **O2^2-**.

### Final Answer:
**O2^2-** does not contain unpaired electrons.

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