For 4s-orbital, m has the value

Options

A. 2
B. 4
C. `-1`
D. 0

Explanation

To determine the value of the magnetic quantum number (m) for the 4s orbital, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Quantum Numbers**:
- The magnetic quantum number (m) is associated with the orientation of the orbital in space.
- The value of m is determined by the azimuthal quantum number (l).

2. **Identify the Azimuthal Quantum Number (l)**:
- The azimuthal quantum number (l) can take values from 0 to (n-1), where n is the principal quantum number.
- For the 4s orbital, the principal quantum number (n) is 4.

3. **Calculate the Value of l**:
- Since n = 4, the possible values for l are:
- l = 0 (s orbital)
- l = 1 (p orbital)
- l = 2 (d orbital)
- l = 3 (f orbital)
- For the s orbital, l = 0.

4. **Determine the Value of m**:
- The magnetic quantum number (m) can take values from -l to +l, including 0.
- Therefore, if l = 0, the possible values for m are:
- m = 0 (since -0 to +0 is just 0).

5. **Conclusion**:
- For the 4s orbital, the value of the magnetic quantum number (m) is 0.

### Final Answer:
The value of m for the 4s orbital is **0**.