Which of the following is paramagnetic?

Options

A. `NO^(+)`
B. CO
C. `O_(2)^(2-)`
D. `B_(2)`

Explanation

To determine which of the given species is paramagnetic, we need to analyze the electron configurations of the species and check for the presence of unpaired electrons. A species is considered paramagnetic if it has one or more unpaired electrons.

### Step-by-Step Solution:

1. **Identify the Species**: We need to evaluate the given species, which include NO+, CO, O2, O2^2-, and B2.

2. **Count the Total Electrons**:
- **NO+**: Nitric oxide (NO) has 11 electrons. Removing one electron for NO+ gives us 10 electrons.
- **CO**: Carbon monoxide (CO) has 10 electrons (6 from oxygen and 4 from carbon).
- **O2**: Molecular oxygen (O2) has 16 electrons (8 from each oxygen atom).
- **O2^2-**: The superoxide ion (O2^2-) has 18 electrons (16 from O2 and 2 additional electrons).
- **B2**: The diatomic boron molecule (B2) has 10 electrons (5 from each boron atom).

3. **Determine Electron Configuration**:
- **NO+**: The electron configuration can be derived from the molecular orbital theory. It has 10 electrons and results in a configuration that has unpaired electrons.
- **CO**: The electron configuration shows that all electrons are paired, making it diamagnetic.
- **O2**: The electron configuration shows that O2 has two unpaired electrons, making it paramagnetic.
- **O2^2-**: In O2^2-, the additional electrons pair up, resulting in no unpaired electrons, making it diamagnetic.
- **B2**: The electron configuration shows that B2 has two unpaired electrons, making it paramagnetic.

4. **Conclusion**:
- From the analysis, we find that both O2 and B2 are paramagnetic due to the presence of unpaired electrons.
- However, since the question asks for which of the following is paramagnetic and does not specify a list, we can conclude that B2 is the correct answer as it was explicitly mentioned in the video.

### Final Answer:
**B2 is paramagnetic.**