Shape of an orbital is given by

Options

A. Principal quantum number
B. Spin quantum number
C. Azimuthal quantum number
D. Magnetic quantum number

Answer

To determine the shape of an orbital, we need to identify which quantum number is responsible for defining it. Let's break down the options provided:

1. **Principal Quantum Number (n)**:
- This quantum number is represented by 'n'.
- It defines the shell in which the electron resides.
- It determines the size and energy of the orbital.
- However, it does not provide information about the shape of the orbital.

2. **Spin Quantum Number (ms)**:
- This quantum number is represented by 'ms'.
- It refers to the orientation of the spin of the electron.
- It does not relate to the shape of the orbital.

3. **Azimuthal Quantum Number (l)**:
- This quantum number is represented by 'l'.
- It identifies the subshell (s, p, d, f) and determines the shape of the orbital.
- For example, 's' orbitals are spherical, 'p' orbitals are dumbbell-shaped, 'd' orbitals have more complex shapes.
- Therefore, this quantum number is crucial for defining the shape of the orbital.

4. **Magnetic Quantum Number (ml)**:
- This quantum number is represented by 'ml'.
- It designates the orientation of the orbital within a given subshell.
- While it provides information about the orientation, it does not define the shape of the orbital.

Based on the analysis above, the correct answer is that the shape of an orbital is given by the **Azimuthal Quantum Number (l)**.

### Final Answer:
The shape of an orbital is given by the **Azimuthal Quantum Number (l)**.