How can the explanatory power of electron theory support scientific realism?

In the philosophy of science, the explanatory power of electron theory serves as a cornerstone for supporting scientific realism by challenging the instrumentalist view that theoretical terms are merely useful fictions.1

Realists argue that one cannot make sense of scientific explanation without acknowledging the reality of unobservable entities. For instance, the ability to understand the character of chemical bonds and the specific ways elements combine relies on taking the proposal of electrons filling shells around nuclei as a literal description of physical reality, rather than a mere façon de parler (way of speaking).1

Furthermore, the success of theories involving electrons—such as those in quantum electrodynamics—provides a powerful argument for realism. Realists contend that if these theories were not at least approximately true, their systematic success in predicting phenomena with extraordinary accuracy would be a coincidence of cosmic proportions, or a "miracle". By treating the electron as a real entity, scientists can account for a broad domain of physical phenomena that would otherwise remain inexplicable, thereby justifying the belief that our best scientific theories accurately describe the unobservable world.231