Question

The quantum number which explains about shape of the orbital is:

• A. Principal quantum number
• B. Angular momentum quantum number
• C. Magnetic quantum number
• D. Spin quantum number

Hint:

Remember the functions of quantum numbers:
• \(n \rightarrow\) Size and energy
• \(l \rightarrow\) Shape
• \(m \rightarrow\) Orientation
• \(s \rightarrow\) Spin

Answer 1

The Correct Option is B

Concept:
Quantum numbers are used to describe electrons in an atom completely. There are four quantum numbers:
• Principal quantum number (\(n\))
• Angular momentum quantum number (\(l\))
• Magnetic quantum number (\(m\))
• Spin quantum number (\(s\)) Each quantum number provides specific information about the electron.

Step 1: Understand the role of each quantum number.
Principal quantum number (\(n\)):
• Represents energy level
• Represents size of orbital Angular momentum quantum number (\(l\)):
• Represents shape of orbital Magnetic quantum number (\(m\)):
• Represents orientation of orbital Spin quantum number (\(s\)):
• Represents spin direction of electron

Step 2: Identify the quantum number related to shape.
The shape of orbitals such as: \[ s,\ p,\ d,\ f \] is determined by the angular momentum quantum number. For example: \[ l=0 \rightarrow s \text{ orbital} \] \[ l=1 \rightarrow p \text{ orbital} \] \[ l=2 \rightarrow d \text{ orbital} \] Hence shape depends on \(l\).

Step 3: Examine the options carefully.
Option (A): Principal quantum number
Determines size and energy level, not shape. Incorrect. Option (B): Angular momentum quantum number
Determines orbital shape. Correct. Option (C): Magnetic quantum number
Determines orientation. Incorrect. Option (D): Spin quantum number
Determines spin direction. Incorrect.

Step 4: Choose the correct answer.
Therefore, the quantum number explaining shape of orbital is: \[ \boxed{\text{Angular momentum quantum number}} \] Hence, \[ \boxed{(2)\ \text{Angular momentum quantum number}} \]