The nitrogen atom in `NH_(3), NH_(2)^(-)` and `NH_(4)^(+)` are all surrounded by eight electrons. When these species are arranged in increasing order of `H-N-H` bond angle, correct order is:

Options

A. `NH_(3), NH_(2)^(-), NH_(4)^(+)`
B. `NH_(4)^(+), NH_(2)^(-), NH_(3)`
C. `NH_(3), NH_(4)^(+), NH_(2)^(-)`
D. `NH_(2)^(-), NH_(3), NH_(4)^(+)`

Explanation

To determine the increasing order of the `H-N-H` bond angle in the species `NH3`, `NH2^(-)`, and `NH4^(+)`, we need to analyze the molecular geometry and the factors affecting the bond angles in these species.

### Step-by-Step Solution:

1. **Identify the Electron Configuration**:
- Nitrogen has 5 valence electrons. In all three species, nitrogen is surrounded by a total of 8 electrons due to bonding and lone pairs.

2. **Analyze NH3 (Ammonia)**:
- In `NH3`, nitrogen is bonded to three hydrogen atoms and has one lone pair.
- The molecular geometry is trigonal pyramidal due to the presence of the lone pair.
- The bond angle is approximately 107 degrees. The lone pair exerts a greater repulsive force than bonding pairs, which reduces the bond angle from the ideal tetrahedral angle of 109.5 degrees.

3. **Analyze NH2^(-) (Amide Ion)**:
- In `NH2^(-)`, nitrogen is bonded to two hydrogen atoms and has two lone pairs.
- The molecular geometry is bent (or angular).
- The bond angle is less than that in `NH3` due to increased lone pair-lone pair repulsion. The bond angle is approximately 104.5 degrees.

4. **Analyze NH4^(+) (Ammonium Ion)**:
- In `NH4^(+)`, nitrogen is bonded to four hydrogen atoms and has no lone pairs.
- The molecular geometry is tetrahedral.
- The bond angle is 109.5 degrees, which is the ideal tetrahedral angle.

5. **Order the Bond Angles**:
- Based on the analysis:
- `NH2^(-)` has the smallest bond angle (approximately 104.5 degrees).
- `NH3` has a bond angle of approximately 107 degrees.
- `NH4^(+)` has the largest bond angle (109.5 degrees).
- Therefore, the increasing order of `H-N-H` bond angles is:
- `NH2^(-) < NH3 < NH4^(+)`

### Final Answer:
The correct increasing order of `H-N-H` bond angles is:
**NH2^(-) < NH3 < NH4^(+)**