Which of the following molecules/ions 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 or ions does not contain unpaired electrons, we will analyze the electronic configuration of each species.

### Step-by-Step Solution:

1. **Identify the Total Number of Electrons:**
- For each molecule/ion, we first need to determine the total number of electrons.

2. **Write the Electron Configuration:**
- For each species, we will write the molecular orbital (MO) configuration based on the total number of electrons.

3. **Check for Unpaired Electrons:**
- After writing the electron configuration, we will check the outermost molecular orbitals to see if there are any unpaired electrons.

4. **Analyze Each Species:**
- **O2^2-:**
- Total electrons = 18
- MO configuration: (σ2s)² (σ*2s)² (σ2p_z)² (π2p_x)² (π2p_y)²
- All electrons are paired. **No unpaired electrons.**

- **B2:**
- Total electrons = 10
- MO configuration: (σ2s)² (σ*2s)² (σ2p_z)² (π2p_x)¹ (π2p_y)¹
- There are unpaired electrons in π2p_x and π2p_y. **Contains unpaired electrons.**

- **N2+:**
- Total electrons = 13
- MO configuration: (σ2s)² (σ*2s)² (σ2p_z)² (π2p_x)¹
- There is one unpaired electron in π2p_x. **Contains unpaired electrons.**

- **O2:**
- Total electrons = 16
- MO configuration: (σ2s)² (σ*2s)² (σ2p_z)² (π2p_x)¹ (π2p_y)¹
- There are unpaired electrons in π2p_x and π2p_y. **Contains unpaired electrons.**

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

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