In which of the following molecules/ions is the bond angle largest?

Options

A. `H_(2)O`
B. `SCl_(2)`
C. `IC l_(2)^(-)`
D. `SnCl_(2)`

Answer

To determine which of the given molecules or ions has the largest bond angle, we will analyze each option step by step.

### Step 1: Analyze H2O
- **Valence Electrons**: Oxygen has 6 valence electrons, and there are 2 hydrogen atoms contributing 1 electron each.
- **Total Valence Electrons**: 6 (O) + 2 (H) = 8
- **Hybridization**: Using the formula:
\[ \text{Hybridization} = \frac{\text{Valence Electrons} + \text{Monovalent Atoms} - \text{Charge}}{2} = \frac{6 + 2 + 0}{2} = 4 \]
This indicates sp³ hybridization.
- **Shape**: H2O has 2 lone pairs and 2 bonding pairs, resulting in a bent shape.
- **Bond Angle**: The bond angle is less than 109.5° due to lone pair-bond pair repulsion.

### Step 2: Analyze SCl2
- **Valence Electrons**: Sulfur has 6 valence electrons, and there are 2 chlorine atoms contributing 1 electron each.
- **Total Valence Electrons**: 6 (S) + 2 (Cl) = 8
- **Hybridization**:
\[ \text{Hybridization} = \frac{6 + 2 + 0}{2} = 4 \]
This also indicates sp³ hybridization.
- **Shape**: SCl2 has 2 lone pairs and 2 bonding pairs, resulting in a bent shape.
- **Bond Angle**: The bond angle is also less than 109.5° due to lone pair-bond pair repulsion.

### Step 3: Analyze ICl2⁻
- **Valence Electrons**: Iodine has 7 valence electrons, and there are 2 chlorine atoms contributing 1 electron each, plus 1 extra electron from the negative charge.
- **Total Valence Electrons**: 7 (I) + 2 (Cl) + 1 (charge) = 10
- **Hybridization**:
\[ \text{Hybridization} = \frac{7 + 2 + 1}{2} = 5 \]
This indicates sp³d hybridization.
- **Shape**: ICl2⁻ has 3 lone pairs and 2 bonding pairs, resulting in a linear shape.
- **Bond Angle**: The bond angle is 180°.

### Step 4: Analyze SnCl2
- **Valence Electrons**: Tin has 4 valence electrons, and there are 2 chlorine atoms contributing 1 electron each.
- **Total Valence Electrons**: 4 (Sn) + 2 (Cl) = 6
- **Hybridization**:
\[ \text{Hybridization} = \frac{4 + 2 + 0}{2} = 3 \]
This indicates sp² hybridization.
- **Shape**: SnCl2 has 1 lone pair and 2 bonding pairs, resulting in a bent shape.
- **Bond Angle**: The bond angle is less than 120° due to lone pair-bond pair repulsion.

### Conclusion
After analyzing all the options:
- H2O: Bond angle < 109.5°
- SCl2: Bond angle < 109.5°
- ICl2⁻: Bond angle = 180°
- SnCl2: Bond angle < 120°

**The largest bond angle is found in ICl2⁻, which is 180°. Therefore, the answer is ICl2⁻.**

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