The valency of nitrogen in nitrogen dioxide `(NO_2)` is

Options

A. One
B. two
C. three
D. four

Answer

To determine the valency of nitrogen in nitrogen dioxide (NO₂), we can follow these steps:

### Step 1: Understand the compound
Nitrogen dioxide (NO₂) consists of one nitrogen atom and two oxygen atoms. We need to find the valency of nitrogen in this compound.

### Step 2: Assign known valency
The valency of oxygen is known to be -2. Since there are two oxygen atoms in nitrogen dioxide, we can express the total contribution of oxygen to the overall charge.

### Step 3: Set up the equation
Let the valency of nitrogen be represented by \( x \). The overall charge of the compound must be neutral (0). Therefore, we can set up the equation based on the contributions of nitrogen and oxygen:
\[ x + 2(-2) = 0 \]
Here, \( 2(-2) \) accounts for the two oxygen atoms.

### Step 4: Simplify the equation
Now, simplify the equation:
\[ x - 4 = 0 \]

### Step 5: Solve for \( x \)
To find the value of \( x \), we can rearrange the equation:
\[ x = 4 \]

### Conclusion
Thus, the valency of nitrogen in nitrogen dioxide (NO₂) is **4**.

---