The bond angles in `NH_(4)^(+)` and `CH_(4)` are same but `NH_(3)` has different bond angle. Why ?

Explanation

To understand why the bond angles in \( \text{NH}_4^+ \) and \( \text{CH}_4 \) are the same while \( \text{NH}_3 \) has a different bond angle, we can analyze the molecular geometry and the influence of lone pairs of electrons.

### Step-by-Step Solution:

1. **Identify the Molecular Geometry of \( \text{NH}_4^+ \) and \( \text{CH}_4 \)**:
- Both \( \text{NH}_4^+ \) (ammonium ion) and \( \text{CH}_4 \) (methane) have a central atom (nitrogen in \( \text{NH}_4^+ \) and carbon in \( \text{CH}_4 \)).
- In both cases, the central atom is surrounded by four bonding pairs of electrons and no lone pairs.

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