Atomic structure refers to the arrangement and composition of atoms, which are the fundamental building blocks of matter. An atom consists of a nucleus, containing protons and neutrons, surrounded by electrons that occupy specific energy levels or shells. The atomic number of an element is determined by the number of protons in its nucleus, while the mass number is the total number of protons and neutrons. Electrons are arranged in electron shells or clouds around the nucleus, and their configuration influences the chemical properties of the element. Ions are formed when atoms gain or lose electrons, resulting in a net electrical charge. The presentation below explores the key concepts of atomic structure, including the roles of subatomic particles and how they interact to form different elements and compounds.
(Simulation by PhET Interactive Simulations, University of Colorado Boulder, licensed under CC-BY-4.0 (https://phet.colorado.edu).)