The maximum number of electrons in an atom which can have n=4 is

Options

A. 4
B. 8
C. 16
D. 32

Answer

To determine the maximum number of electrons in an atom with a principal quantum number \( n = 4 \), we can use the formula for the maximum number of electrons in a shell:

### Step-by-Step Solution:

1. **Understand the Principal Quantum Number (n)**:
- The principal quantum number \( n \) indicates the energy level or shell of an electron in an atom. For \( n = 4 \), we are looking at the fourth energy level.

2. **Use the Formula for Maximum Electrons**:
- The maximum number of electrons that can occupy a shell is given by the formula:
\[ \text{Maximum electrons} = 2n^2 \]

3. **Substitute the Value of n**:
- Here, \( n = 4 \). Substitute this value into the formula:
\[ \text{Maximum electrons} = 2 \times (4^2) \]

4. **Calculate \( 4^2 \)**:
- Calculate \( 4^2 \):
\[ 4^2 = 16 \]

5. **Multiply by 2**:
- Now, multiply by 2:
\[ 2 \times 16 = 32 \]

6. **Conclusion**:
- Therefore, the maximum number of electrons in an atom with \( n = 4 \) is **32**.

### Final Answer:
The maximum number of electrons in an atom which can have \( n = 4 \) is **32**.