Atomic theory posits that atoms exist in quantized energy levels determined by electron configurations around a nucleus comprising protons and neutrons. The transition between these states, such as absorption from the ground state to excited states or spontaneous emission via photon release, is governed by specific conservation of energy principles where excitation lifetimes define metastable conditions. This framework constitutes the fundamental quantum mechanical description of matter required for understanding atomic interaction mechanisms within physics and chemistry.
Prerequisite chain context: requires Atomic Theory Basics in General Chemistry.