The term that describes the arrangement of electrons in an atom is called electron configuration. This configuration outlines how electrons are distributed among the various energy levels and sublevels surrounding the nucleus. The arrangement follows the principles of Aufbau, Pauli exclusion, and Hund's rule to determine the most stable distribution of electrons. Understanding electron configurations is essential for predicting chemical behavior, bonding, and the properties of elements. It is a fundamental concept in chemistry, particularly in the study of periodic trends and reactivity.