Which principal quantum number (n) corresponds to the lowest possible energy level that an electron can occupy in an atom?

• A. n = 2
• B. n = 1
• C. n = 3
• D. n = 0

Answer: (B)

Verified step by step guidance

1. Recall that the principal quantum number, denoted as \(n\), indicates the main energy level or shell of an electron in an atom.
2. Understand that \(n\) can only take positive integer values starting from 1, i.e., \(n = 1, 2, 3, \ldots\); it cannot be zero or negative.
3. Recognize that the lowest energy level corresponds to the smallest value of \(n\), which is \(n = 1\); this is also called the ground state.
4. Note that higher values of \(n\) correspond to higher energy levels and electrons farther from the nucleus.
5. Therefore, the principal quantum number \(n = 1\) corresponds to the lowest possible energy level an electron can occupy in an atom.