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 options: N2+, O2-, O2, and B2.

### Step 1: Determine the total number of electrons for each species
- **N2+**: Nitrogen (N) has 7 electrons, so N2 has a total of 14 electrons. Since N2+ has lost one electron, it has 13 electrons.
- **O2-**: Oxygen (O) has 8 electrons, so O2 has a total of 16 electrons. Since O2- has gained one electron, it has 17 electrons.
- **O2**: As mentioned, O2 has 16 electrons.
- **B2**: Boron (B) has 5 electrons, so B2 has a total of 10 electrons.

### Step 2: Write the molecular orbital configurations
1. **N2+ (13 electrons)**:
- Molecular orbital configuration: (σ1s)² (σ*1s)² (σ2s)² (σ*2s)² (σ2p)² (π2p)² (π*2p)¹
- Unpaired electrons: 1 (in π*2p)

2. **O2- (17 electrons)**:
- Molecular orbital configuration: (σ1s)² (σ*1s)² (σ2s)² (σ*2s)² (σ2p)² (π2p)² (π*2p)² (π*2p)¹
- Unpaired electrons: 0 (all electrons are paired)

3. **O2 (16 electrons)**:
- Molecular orbital configuration: (σ1s)² (σ*1s)² (σ2s)² (σ*2s)² (σ2p)² (π2p)² (π*2p)¹ (π*2p)¹
- Unpaired electrons: 2 (in π*2p)

4. **B2 (10 electrons)**:
- Molecular orbital configuration: (σ1s)² (σ*1s)² (σ2s)² (σ*2s)² (σ2p)² (π2p)¹ (π2p)¹
- Unpaired electrons: 2 (in π2p)

### Step 3: Identify the species with no unpaired electrons
From the analysis:
- N2+ has 1 unpaired electron.
- O2- has 0 unpaired electrons.
- O2 has 2 unpaired electrons.
- B2 has 2 unpaired electrons.

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

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