Medical Chemistry Practice Test

Electron configuration notation describes how electrons occupy the atom’s energy levels and subshells around the nucleus. Each segment shows the energy level (the number), the orbital type (s, p, d, f), and how many electrons are in that subshell (the superscript). For example, 1s^2 2s^2 2p^6 shows exactly how many electrons sit in the 1s, 2s, and 2p subshells, following the filling rules that govern the arrangement. This notation is about the distribution of electrons in the atom, not about how protons or neutrons are arranged in the nucleus, and it isn’t a direct statement of spin orientation, though spin pairing is constrained by quantum rules.