What is the term for a division of a principal energy level that contains one or more orbitals?

The correct term for a division of a principal energy level that contains one or more orbitals is "sublevel." In atomic theory, principal energy levels can be thought of as the major energy shells around an atom’s nucleus, which are designated by the principal quantum number. Each principal energy level is further divided into sublevels, which are designated by letters such as s, p, d, and f.

For instance, the first principal energy level (n=1) has one sublevel (1s), while the second principal energy level (n=2) contains two sublevels (2s and 2p). Each sublevel can contain one or more orbitals, where each orbital can hold up to two electrons with opposite spins. This descriptive structure allows chemists to understand how electrons are distributed in an atom, influence its chemical properties, and predict the behavior of elements.

In contrast, "orbital" refers specifically to a region within a sublevel where there is a high probability of finding an electron, but it does not encompass the entire sublevel itself. "Quantum number" describes specific values that characterize the energy levels and sublevels but does not itself represent any physical structure, while "electron configuration" is a notation that represents