Sublevels are divisions within electron shells in an atom, which help to organize the arrangement of electrons. Each shell can contain one or more sublevels, designated as s, p, d, and f. The number of sublevels increases with the principal quantum number, meaning higher energy levels have more sublevels available for electrons. Each sublevel has a specific shape and can hold a certain number of electrons. For example, the s sublevel can hold 2 electrons, the p sublevel can hold 6, the d sublevel can hold 10, and the f sublevel can hold 14. Understanding sublevels is essential for grasping the structure of atoms and their chemical behavior.