ABSTRACT
The Bohr model was hailed as revolutionary, but flaws in the model were apparent after only a short time. The limitations of the Bohr model are inherent in Bohr’s, and early 20th-century physics’, conception of electrons purely as particles. With the appreciation of wave–particle duality, a new quantum mechanical approach – Schrödinger's wavefunctions and Heisenberg's matrix mechanics – led to a new understanding of the electronic structure of atoms. This chapter develops this new quantum mechanical model and provides readers with a modern understanding of electronic structure with an emphasis on the energy of electrons as an explanatory device for understanding core electrons (those unavailable for chemistry) and valence electrons (those involved in chemical reactions). The periodic patterns in electron configurations are then used to provide an understanding of the repeating patterns of reactivity in the periodic table and the patterns in common charges for monatomic ions of the elements.
