To determine which molecule is linear among the given options, we will analyze each molecule step by step.
### Step 1: Analyze NO2 (Nitrogen Dioxide)
- **Valence Electrons**: Nitrogen has 5 valence electrons, and each oxygen has 6 valence electrons. Thus, total valence electrons = 5 + 2(6) = 17.
- **Lewis Structure**: In NO2, nitrogen forms one double bond with one oxygen and a single bond with the other oxygen. This leaves one unpaired electron on nitrogen.
- **Hybridization**: The nitrogen atom has 2 bond pairs and 1 lone electron, leading to a steric number of 3. The hybridization is sp².
- **Geometry**: The geometry is trigonal planar, but due to the presence of the lone electron, the shape is bent.
**Conclusion**: NO2 is not linear.
### Step 2: Analyze ClO2 (Chlorine Dioxide)
- **Valence Electrons**: Chlorine has 7 valence electrons, and each oxygen has 6 valence electrons. Total = 7 + 2(6) = 19.
- **Lewis Structure**: Chlorine forms one double bond with one oxygen and a single bond with the other oxygen, leaving one lone electron on chlorine.
- **Hybridization**: Chlorine has 2 bond pairs and 1 lone electron, leading to a steric number of 3. The hybridization is sp².
- **Geometry**: The geometry is trigonal planar, but the presence of the lone electron results in a bent shape.
**Conclusion**: ClO2 is not linear.
### Step 3: Analyze CO2 (Carbon Dioxide)
- **Valence Electrons**: Carbon has 4 valence electrons, and each oxygen has 6 valence electrons. Total = 4 + 2(6) = 16.
- **Lewis Structure**: In CO2, carbon forms two double bonds with each oxygen atom, resulting in no lone pairs on carbon.
- **Hybridization**: Carbon has 2 bond pairs and 0 lone pairs, leading to a steric number of 2. The hybridization is sp.
- **Geometry**: The geometry is linear.
**Conclusion**: CO2 is linear.
### Step 4: Analyze H2S (Hydrogen Sulfide)
- **Valence Electrons**: Sulfur has 6 valence electrons, and each hydrogen has 1 valence electron. Total = 6 + 2(1) = 8.
- **Lewis Structure**: Sulfur forms two single bonds with hydrogen and has two lone pairs.
- **Hybridization**: Sulfur has 2 bond pairs and 2 lone pairs, leading to a steric number of 4. The hybridization is sp³.
- **Geometry**: The geometry is tetrahedral, but the presence of lone pairs results in a bent shape.
**Conclusion**: H2S is not linear.
### Final Answer
Among the analyzed molecules, the only linear molecule is **CO2**.
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