For `n=4` , which one of the following values of l is not possible ?

Options

A. 1
B. 2
C. 3
D. 4

Answer

To determine which value of the azimuthal quantum number \( l \) is not possible for \( n = 4 \), we will follow these steps:

### Step 1: Understand the Quantum Numbers
The principal quantum number \( n \) indicates the energy level of an electron in an atom. The azimuthal quantum number \( l \) (also known as the angular momentum quantum number) determines the shape of the orbital and can take on integer values from \( 0 \) to \( n-1 \).

### Step 2: Determine Possible Values of \( l \)
For a given principal quantum number \( n \), the possible values of \( l \) are:
\[ l = 0, 1, 2, \ldots, (n-1) \]
For \( n = 4 \):
\[ l = 0, 1, 2, 3 \]
This means the possible values of \( l \) are \( 0, 1, 2, \) and \( 3 \).

### Step 3: Identify the Values of \( l \) Given in the Question
Assuming the question provides specific values for \( l \), we need to compare these values against the possible values derived in Step 2.

### Step 4: Conclusion
If one of the values provided in the options is \( 4 \), then it is not possible since the maximum value of \( l \) for \( n = 4 \) is \( 3 \).

### Final Answer
The value of \( l \) that is not possible for \( n = 4 \) is \( 4 \).

---