Like reactionals, elemental magic is one of the big parts of the magical systems used in Tarsan, Gepaul, and Kormar. They are distinct since they equate more to the modern day periodic table of elementals instead of the “classical” elementals of earth, air, fire, and water. In specific, fire is a reactional and air is… squishy because it acts as both an elemental (oxygen) and a reactional (wind).
Ultimately, the separation of the two is how I'm representing a purely magical society discovering chemical reactions, the periodic table, and delving deeper into the world until they realize elementals are really a complex classification system on the order of genus and species or even a complex system of taxonomies.
In the world, no one will ever know the “full” answer much like no one knows how everything works in our world. This came from my dad's work with the particle accelerator at Aragon as scientists tried to learn what made up atoms or even trying to look at the building blocks of quarks.