Which property of an electron in an atom is indicated by the principal quantum number (n)?

• A. The shape of the orbital occupied by the electron
• B. The spin direction of the electron
• C. The energy level or shell in which the electron resides
• D. The orientation of the orbital in space

Answer: (C)

Verified step by step guidance

1. Understand that the principal quantum number, denoted as \(n\), is one of the four quantum numbers used to describe the unique quantum state of an electron in an atom.
2. Recall that \(n\) primarily indicates the main energy level or shell of the electron, which corresponds to the relative distance of the electron from the nucleus and its energy.
3. Recognize that other quantum numbers describe different properties: the azimuthal quantum number (\(l\)) describes the shape of the orbital, the magnetic quantum number (\(m_l\)) describes the orientation of the orbital in space, and the spin quantum number (\(m_s\)) describes the spin direction of the electron.
4. Therefore, the principal quantum number \(n\) tells us about the energy level or shell where the electron is located, which is related to the size and energy of the orbital.
5. Summarize that the correct property indicated by \(n\) is the energy level or shell of the electron, not the shape, orientation, or spin.