The correct order of A-O-A bond angle of (A=H,F or Cl)

Options

A. `H_(2)OgtCl_(2)OgtF_(2)O`
B. `Cl_(2)OgtH_(2)OgtF_(2)O`
C. `F_(2)OgtCl_(2)gtH_(2)O`
D. `F_(2)gtH_(2)OgtCl_(2)O`

Answer

To determine the correct order of A-O-A bond angles for A being H, F, or Cl, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds we need to analyze are H2O (water), Cl2O (dichlorine monoxide), and F2O (difluorine monoxide).

2. **Draw Lewis Structures**:
- For H2O: Oxygen (O) is the central atom with two hydrogen (H) atoms attached. Oxygen has two lone pairs.
- For Cl2O: Oxygen is the central atom with two chlorine (Cl) atoms attached. Oxygen has two lone pairs.
- For F2O: Oxygen is the central atom with two fluorine (F) atoms attached. Oxygen has two lone pairs.

3. **Analyze Electronegativity**:
- Oxygen is more electronegative than hydrogen, which means H will not attract electrons from O.
- Chlorine is less electronegative than oxygen, so Cl will not attract electrons from O as strongly as F does.
- Fluorine is more electronegative than oxygen, meaning it will pull electron density away from O.

4. **Consider Lone Pair Repulsion**:
- In Cl2O, the larger size of Cl and the presence of lone pairs on O will lead to increased repulsion, resulting in a larger bond angle.
- In F2O, the strong electronegativity of F reduces the electron density around O, leading to less repulsion between the lone pairs, resulting in a smaller bond angle than H2O.
- In H2O, the lone pairs on O create significant repulsion, leading to a larger bond angle compared to F2O.

5. **Determine the Bond Angle Order**:
- From the analysis, we can conclude that Cl2O has the largest bond angle due to the size and lone pair repulsion of Cl.
- H2O has a larger bond angle than F2O because of the lesser electronegativity of H compared to F.
- Therefore, the order of bond angles is:
\[ \text{Cl}_2\text{O} > \text{H}_2\text{O} > \text{F}_2\text{O} \]

### Final Answer:
The correct order of A-O-A bond angles is:
\[ \text{Cl}_2\text{O} > \text{H}_2\text{O} > \text{F}_2\text{O} \]