Abstract

This paper performs a historical study of the attempts made by Thomson and Bohr to explain the Periodic Table in terms of the electronic configurations of chemical elements. Specifically, Thomson’s early theoretical ideas about the electronic arrangements of atoms are initially outlined. This system gave way to the first quantum constrains introduced by Bohr in 1913. It is discussed how Bohr eventually revised this initial work on this topic ten years later. Then, it is presented a concise historical account of the progressive incorporation of quantum numbers in the different theories of the electronic structure of elements. In this regard, the contributions made by Sommerfeld, Stoner and Pauli are examined. Finally, the Madelung rule is analyzed, focusing on both how it has normally been used to teach students the atomic electronic configurations and its limitations. These shortcomings are usually not considered in chemistry textbooks. It is reported how this neglect generates several incorrect teaching assumptions.