Which of the following hydrides has the largent bond angle ?

Options

A. `H_2Se`
B. `H_2S`
C. `H_2Te`
D. `H_2O`

Explanation

To determine which hydride has the largest bond angle, we will analyze the structures and properties of the given hydrides: H2O (water), H2S (hydrogen sulfide), H2Se (hydrogen selenide), and H2Te (hydrogen telluride).

### Step-by-Step Solution:

1. **Identify the Central Atom**:
- In each hydride, the central atom is the element from Group 16 of the periodic table (O, S, Se, Te).
- For H2O, the central atom is oxygen (O).
- For H2S, the central atom is sulfur (S).
- For H2Se, the central atom is selenium (Se).
- For H2Te, the central atom is tellurium (Te).

**Hint**: Identify the central atom in each hydride, which is the element bonded to hydrogen.

2. **Draw the Molecular Structures**:
- H2O: Oxygen has 2 hydrogen atoms and 2 lone pairs of electrons.
- H2S: Sulfur has 2 hydrogen atoms and 2 lone pairs of electrons.
- H2Se: Selenium has 2 hydrogen atoms and 2 lone pairs of electrons.
- H2Te: Tellurium has 2 hydrogen atoms and 2 lone pairs of electrons.

**Hint**: Sketch the Lewis structures to visualize the arrangement of atoms and lone pairs.

3. **Analyze Electronegativity**:
- The electronegativity of the central atoms decreases as we move down the group: O > S > Se > Te.
- Higher electronegativity means that the central atom pulls the bonding electrons closer, leading to greater repulsion between the bond pairs.

**Hint**: Recall that higher electronegativity results in stronger attraction of bonding electrons, affecting bond angles.

4. **Consider Lone Pair Repulsion**:
- In H2O, the bond angle is influenced by the strong repulsion between the lone pairs and the bonding pairs, which leads to a larger bond angle.
- As we move down the group to H2S, H2Se, and H2Te, the bond angles decrease due to weaker lone pair repulsion and lower electronegativity.

**Hint**: Remember that lone pairs exert greater repulsive forces than bonding pairs, affecting the bond angles.

5. **Determine the Bond Angles**:
- H2O has a bond angle of approximately 104.5°.
- H2S has a bond angle of approximately 92°.
- H2Se has a bond angle of approximately 89°.
- H2Te has a bond angle of approximately 88°.

**Hint**: Look up the typical bond angles for these hydrides to confirm your findings.

6. **Conclusion**:
- The bond angle decreases from H2O to H2Te due to decreasing electronegativity and increasing size of the central atom.
- Therefore, the hydride with the largest bond angle is H2O.

**Final Answer**: The hydride with the largest bond angle is **H2O (water)**.