Historical Evolution of Atomic Models

Abstract

The concept of the atom is one of the oldest in history and is currently the one that prevails in chemistry teaching. The atomic model has evolved since Democritus and Plato, undergoing several modifications to align with observations made at each time. In the modern era, some of the most significant figures in this topic are, among others, John Dalton, John J. Thomson, Ernest Rutherford, Niels Bohr, Arnold Sommerfeld and Erwin Schrödinger, whose proposed atomic models are often taught in high school courses and in various undergraduate disciplines around the world. However, the current approach to this topic can lead students to incorrect perceptions, as the models and their principles are presented without much discussion about their justifications and without presenting the controversies that surround their development. This article presents the evolution of atomic models, highlighting their characteristics and correcting existing misconceptions about Dalton and Thomson models as they are taught today. Special emphasis was given to original articles (primary sources) and works based on them.