Question

The quantum number which is responsible for the size of electron cloud is

• A. spin
• B. azimuthal
• C. principal
• D. magnetic

Answer 1

Answer: (C)

Principal quantum number $(n)$ determines the size and main energy level or shell. Azimuthal or angular quantum number $(l)$ gives the sub-shell or sub-level and also determines the shape of the orbitals.
Magnetic quantum number $(m)$ refers to the different orientations of the orbitals in space. Spin quantum number $(s)$ describes the : pin orientation of the electron.