The `O-N-O` bond angle in the nitrite ion, `NO_(2)^(-)`, is closest to :

Options

A. `N_(2)O`
B. `NO_(2)^(+)`
C. `NO_(2)^(-)`
D. `NO_(3)^(-)`

Explanation

To determine the `O-N-O` bond angle in the nitrite ion, `NO2^(-)`, we can follow these steps:

### Step 1: Determine the Valence Electrons
First, we need to calculate the total number of valence electrons in the nitrite ion (`NO2^(-)`).

- Nitrogen (N) has 5 valence electrons.
- Each Oxygen (O) has 6 valence electrons, and there are two Oxygens.
- Since the ion has a negative charge, we add one extra electron.

**Calculation:**
\[ \text{Total valence electrons} = 5 + (6 \times 2) + 1 = 18 \]

### Step 2: Determine the Number of Sigma Bonds and Lone Pairs
Next, we need to determine how many sigma bonds can be formed and how many lone pairs are present.

- Each sigma bond accounts for 2 electrons.
- To find the number of sigma bonds, we divide the total valence electrons by 2.

**Calculation:**
\[ \text{Number of sigma bonds} = \frac{18}{2} = 9 \]
Since we are looking for the number of sigma bonds in the molecule, we need to consider the structure.

### Step 3: Draw the Lewis Structure
In the nitrite ion, the structure is as follows:
- The nitrogen atom is in the center.
- It forms one double bond with one oxygen and one single bond with the other oxygen.
- The single-bonded oxygen carries a negative charge.

The structure looks like this:
```
O
||
N - O^(-)
```

### Step 4: Determine the Geometry
The presence of one lone pair on the nitrogen atom affects the geometry of the molecule. The geometry around the nitrogen atom is bent due to the lone pair.

### Step 5: Measure the Bond Angle
The `O-N-O` bond angle in the nitrite ion is influenced by the lone pair and is expected to be less than the typical bond angle of 120 degrees found in trigonal planar geometries.

### Conclusion
Thus, the `O-N-O` bond angle in the nitrite ion (`NO2^(-)`) is closest to **less than 120 degrees**.

### Final Answer
The `O-N-O` bond angle in the nitrite ion, `NO2^(-)`, is closest to **120 degrees**.

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