The bond angles of `NH_3,NH_4^(+)and NH_2^(-)` are in the order

Options

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

Answer

To determine the bond angles of NH3 (ammonia), NH4+ (ammonium ion), and NH2- (amide ion), we need to analyze the molecular geometry and the presence of lone pairs of electrons around the nitrogen atom in each species.

### Step 1: Analyze NH3 (Ammonia)
- **Molecular Geometry**: NH3 has a trigonal pyramidal shape due to one lone pair of electrons on the nitrogen atom.
- **Bonding**: Nitrogen has 5 valence electrons, forms three bonds with hydrogen, and has one lone pair.
- **Bond Angle**: The bond angle in NH3 is approximately 107 degrees due to the repulsion between the lone pair and the bonding pairs.

### Step 2: Analyze NH4+ (Ammonium Ion)
- **Molecular Geometry**: NH4+ has a tetrahedral shape because it has no lone pairs; all four valence electrons of nitrogen are used for bonding.
- **Bonding**: The positive charge indicates that one electron is removed, resulting in four bonding pairs with hydrogen.
- **Bond Angle**: The bond angle in NH4+ is approximately 109.5 degrees, which is typical for a tetrahedral arrangement.

### Step 3: Analyze NH2- (Amide Ion)
- **Molecular Geometry**: NH2- has a bent shape due to the presence of two lone pairs of electrons on the nitrogen atom.
- **Bonding**: The nitrogen has 5 valence electrons, forms two bonds with hydrogen, and has two lone pairs.
- **Bond Angle**: The bond angle in NH2- is less than that of NH3, approximately 104 degrees, due to increased lone pair-lone pair repulsion.

### Step 4: Compare the Bond Angles
- **Order of Bond Angles**: Based on the analysis:
- NH4+ has the largest bond angle (109.5 degrees).
- NH3 has a smaller bond angle (107 degrees).
- NH2- has the smallest bond angle (104 degrees).

Thus, the order of bond angles is:
**NH4+ > NH3 > NH2-**

### Final Answer:
The bond angles of NH3, NH4+, and NH2- are in the order: **NH4+ > NH3 > NH2-**.

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