Which of the following molecules/ins does not contain unpaired electrons?

Options

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

Explanation

To determine which of the given molecules does not contain unpaired electrons, we will analyze the molecular orbital configurations of each molecule using molecular orbital theory.

### Step-by-Step Solution:

1. **Identify the molecules and their electron counts**:
- O2^2-: 18 electrons
- B2: 10 electrons
- N2: 14 electrons
- O2: 16 electrons

2. **Write the molecular orbital configurations**:
- For O2^2- (18 electrons):
- Configuration: σ1s², σ*1s², σ2s², σ*2s², σ2p_z², π2p_x², π2p_y²
- All electrons are paired. **No unpaired electrons**.

- For B2 (10 electrons):
- Configuration: σ1s², σ*1s², σ2s², σ*2s², π2p_x¹, π2p_y¹
- There are unpaired electrons in π2p_x and π2p_y. **Contains unpaired electrons**.

- For N2 (14 electrons):
- Configuration: σ1s², σ*1s², σ2s², σ*2s², σ2p_z², π2p_x¹, π2p_y¹
- There is an unpaired electron in π2p_x and π2p_y. **Contains unpaired electrons**.

- For O2 (16 electrons):
- Configuration: σ1s², σ*1s², σ2s², σ*2s², σ2p_z², π2p_x¹, π2p_y¹
- There is an unpaired electron in π2p_x and π2p_y. **Contains unpaired electrons**.

3. **Conclusion**:
- The only molecule that does not contain unpaired electrons is **O2^2-**.

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