The paramagnetic species is

Options

A. `SiO_(2)`
B. `TiO_(2)`
C. `BaO_(2)`
D. `KO_(2)`

Answer

To determine the paramagnetic species from the given options, we need to identify which species has unpaired electrons. Paramagnetic species are characterized by the presence of one or more unpaired electrons in their electronic configuration.

### Step-by-Step Solution:

1. **Understand Paramagnetism**:
- Paramagnetic species have unpaired electrons, while diamagnetic species have all electrons paired.

2. **Analyze the Given Options**:
- The options provided are SiO2, TiO2, BaO2, and KO2.

3. **Determine the Oxidation States**:
- For SiO2: Silicon (Si) is in the +4 oxidation state, and oxygen (O) is in the -2 oxidation state.
- For TiO2: Titanium (Ti) is in the +4 oxidation state, and oxygen (O) is in the -2 oxidation state.
- For BaO2: Barium (Ba) is in the +2 oxidation state, and oxygen (O) is in the -1 oxidation state (peroxide).
- For KO2: Potassium (K) is in the +1 oxidation state, and O2 is in the -1 oxidation state (superoxide).

4. **Write the Electronic Configuration for O2 and its Ions**:
- For O2: The electronic configuration is (σ1s)² (σ1s*)² (σ2s)² (σ2s*)² (σ2p z)² (π2p x)² (π2p y)².
- For O2²- (peroxide): This has 18 electrons, and all electrons are paired.
- For O2⁻ (superoxide): This has 17 electrons. The electronic configuration will have one unpaired electron.

5. **Identify Unpaired Electrons**:
- SiO2: All electrons are paired (diamagnetic).
- TiO2: All electrons are paired (diamagnetic).
- BaO2: All electrons are paired (diamagnetic).
- KO2: Has one unpaired electron in the π* orbital (paramagnetic).

6. **Conclusion**:
- The only species with unpaired electrons is KO2, making it the paramagnetic species.

### Final Answer:
The paramagnetic species is **KO2**.