Which of the following quantum numbers describes the shape of an atomic orbital?

• A. Angular momentum quantum number (l)
• B. Principal quantum number (n)
• C. Spin quantum number (m_s)
• D. Magnetic quantum number (m_l)

Answer: (A)

Verified step by step guidance

1. Understand that quantum numbers are used to describe the properties of atomic orbitals and the electrons within them.
2. Recall the four quantum numbers: Principal quantum number (\(n\)), Angular momentum quantum number (\(l\)), Magnetic quantum number (\(m_l\)), and Spin quantum number (\(m_s\)).
3. Identify the role of each quantum number: \(n\) describes the energy level and size of the orbital, \(l\) describes the shape of the orbital, \(m_l\) describes the orientation of the orbital in space, and \(m_s\) describes the spin of the electron.
4. Focus on the angular momentum quantum number (\(l\)), which determines the shape of the atomic orbital (e.g., \(s\), \(p\), \(d\), \(f\) orbitals correspond to \(l=0,1,2,3\) respectively).
5. Conclude that the quantum number describing the shape of an atomic orbital is the angular momentum quantum number (\(l\)).