What is the smallest possible value of the principal quantum number n for an f electron?

• A. 6
• B. 4
• C. 3
• D. 5

Answer: (B)

Verified step by step guidance

1. Recall that the principal quantum number \(n\) determines the energy level or shell of an electron in an atom.
2. Understand that the azimuthal (angular momentum) quantum number \(l\) defines the subshell type: \(l=0\) for s, \(l=1\) for p, \(l=2\) for d, and \(l=3\) for f orbitals.
3. Since \(l\) must be less than \(n\) (i.e., \(l < n\)), for an f electron where \(l=3\), the smallest possible \(n\) must satisfy \(n > 3\).
4. Therefore, the smallest principal quantum number \(n\) for an f electron is \(n=4\).
5. This means the first energy level that contains f orbitals is the fourth shell.