The bond angle follows the order:
`NH_(4)^(+) gt NH_(3) gt NH_(2)^(-)`

Explanation

To determine the bond angle order for the species NH₄⁺, NH₃, and NH₂⁻, we need to analyze the molecular geometry and the effects of lone pairs on bond angles.

### Step-by-Step Solution:

1. **Identify the Molecular Geometry:**
- **NH₄⁺ (Ammonium ion):** It has four hydrogen atoms bonded to a nitrogen atom with no lone pairs. The molecular geometry is tetrahedral.
- **NH₃ (Ammonia):** It has three hydrogen atoms and one lone pair on the nitrogen atom. The molecular geometry is trigonal pyramidal.
- **NH₂⁻ (Amide ion):** It has two hydrogen atoms and two lone pairs on the nitrogen atom. The molecular geometry is bent.
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