Which have linear structure?

Options

A. `NO_(2)`
B. `NO_(2)^(+)`
C. `NO_(2)^(-)`
D. `PbCl_(2)`

Explanation

To determine which of the given compounds have a linear structure, we will analyze each compound one by one based on their molecular geometry.

### Step-by-Step Solution:

1. **Analyze NO2 (Nitrogen Dioxide)**:
- NO2 has one nitrogen atom bonded to two oxygen atoms.
- The nitrogen atom has one unpaired electron, leading to repulsion between the bond pairs and the unpaired electron.
- This results in an angular (bent) shape rather than a linear structure.
- **Conclusion**: NO2 is not linear.

2. **Analyze NO2+ (Nitronium Ion)**:
- NO2+ is formed by removing one electron from NO2.
- With the removal of the unpaired electron, there are no lone pairs or unpaired electrons left on the nitrogen.
- This allows the two oxygen atoms to be positioned 180 degrees apart, resulting in a linear structure.
- **Conclusion**: NO2+ is linear.

3. **Analyze NO2- (Nitrite Ion)**:
- NO2- has one nitrogen atom bonded to two oxygen atoms, with one of the oxygen atoms carrying a negative charge.
- The nitrogen atom in NO2- has one lone pair of electrons.
- The presence of this lone pair leads to repulsion between the lone pair and the bond pairs, resulting in an angular shape.
- **Conclusion**: NO2- is not linear.

4. **Analyze PbCl2 (Lead(II) Chloride)**:
- PbCl2 has a lead atom bonded to two chlorine atoms.
- Lead can have lone pairs due to its position in the carbon family (Group 14).
- The presence of a lone pair on lead will cause repulsion with the bond pairs, resulting in a bent shape rather than a linear structure.
- **Conclusion**: PbCl2 is not linear.

### Final Answer:
The only compound that has a linear structure is **NO2+**.

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