The molecule having the largest bond angle is :

Options

A. `H_(2)O`
B. `H_(2)S`
C. `H_(2)Se`
D. `H_(2)Te`

Answer

To determine which molecule has the largest bond angle among the elements of Group 16 (the oxygen family), we can analyze the molecular geometry and the factors affecting bond angles in these molecules.

### Step-by-Step Solution:

1. **Identify the Group 16 Elements**: The elements in Group 16 include oxygen (O), sulfur (S), selenium (Se), and tellurium (Te). We will focus on their common compounds, particularly water (H₂O), hydrogen sulfide (H₂S), and similar compounds.

2. **Determine the Valence Electrons**:
- Oxygen has 6 valence electrons.
- Sulfur has 6 valence electrons as well.
- Selenium and tellurium also have 6 valence electrons.

3. **Draw the Lewis Structures**:
- For H₂O: Oxygen forms two single bonds with hydrogen and has two lone pairs. The structure is bent due to these lone pairs.
- For H₂S: Sulfur forms two single bonds with hydrogen and has two lone pairs as well, but the bond angle is affected differently due to larger atomic size.
- For H₂Se and H₂Te: These will have similar structures with larger bond angles due to the increasing size of the central atom.

4. **Analyze the Bond Angles**:
- In H₂O, the bond angle is approximately 104.5° due to the repulsion between the two lone pairs and the two bond pairs.
- In H₂S, the bond angle is about 92° because the larger size of sulfur leads to less repulsion between the bonding pairs.
- As we move down the group to H₂Se and H₂Te, the bond angles continue to decrease due to the increasing size of the central atom.

5. **Conclusion**:
- The molecule with the largest bond angle among these is H₂O (water), with a bond angle of approximately 104.5°. The reason for this is the strong lone pair-bond pair repulsion in water, which is greater than in the other molecules due to the higher electronegativity of oxygen compared to sulfur, selenium, and tellurium.

### Final Answer:
The molecule having the largest bond angle is **H₂O (water)**.

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