STEM (Spin Torus Energy Model) is an energy-centric approach to atomic Physics that is based upon the simple hypothesis that ‘there is only one type of energy-generating material’, and that material is electromagnetic in nature and has been called energen. STEM proposes that, rather than positively charged matter (e.g. positrons and protons) being distinctly different to negatively charged matter (e.g. electrons), all forms of matter are to be related to energen-based structures or various combinations thereof. All fundamental particles, composite particles, electromagnetic fields, electromagnetic radiation (EMR) and matter are thus considered to be derived from and definable in terms of energen concentrations, flow patterns or combinations thereof.STEM is a pragmatic approach whose ‘proof of concept’ has been in terms of how well it sits with existing mathematical theory (such as the QM wave equations), existing experimental observations, and the theory behind the practical applications of the applied Science and engineering areas. STEM has resulted in physical models for fundamental and composite particles but, being a pragmatic approach, very little new mathematical theory has accompanied its development. Whereas conventional Atomic Physics tends to be disjointed and conflicted, the beauty of the STEM approach is that it provides consistent seamless explanations across the applied Science areas.This paper is the first of three volumes covering a wide range of Physics-related phenomena. Volume 1 proposes and develops a toroidal structure for the electron, and applies it to explain electricity and electromagnetism. Volume 2 addresses atomic structure, developing a structure for quarks, nucleons and atomic nuclei. Volume 3 addresses the physical nature of light and related forms of electromagnetic radiation (EMR).