Question

The quantum number which describes the shape of an atomic orbital is indicated by the symbol

• A. $l$
• B. $m$
• C. $m_s$
• D. $n$

Hint:

To remember the sequence, think of an address: $n$ is the City (Size/Energy), $l$ is the Street (Shape), $m_l$ is the House Number (Orientation), and $m_s$ is the Person (Spin).

Answer 1

The Correct Option is A

1. Principal Quantum Number ($n$): Indicates the main energy level or shell and determines the size of the orbital.

2. Azimuthal (Subsidiary) Quantum Number ($l$): This is the quantum number asked for in the question. It describes the

shape of the orbital and defines the subshell (s, p, d, f).

• $l = 0$: s-orbital (spherical)

• $l = 1$: p-orbital (dumb-bell)

• $l = 2$: d-orbital (double dumb-bell)

3. Magnetic Quantum Number ($m$ or $m_l$): Describes the orientation of the orbital in three-dimensional space.