The term atom comes from the negating prefix a- and the root word, tomi ancient Greek for a cut or slice. (compare Tomography) — that is, not divisable into parts. Today we know that atoms can indeed be divided (though not easily) into subatomic parts, but the term has allowed a logical entry into the cosmos of the physical universe since ancient times. In Basic atomic physics, we will introduce theoretical (atomic) physics to the reader who is "not conversant with the mathematical apparatus of theoretical physics [1]" but keenly interested and determined to learn the topic. See the School of Physics for this article's placement within the curriculum.
Early thinkers, such as Democritus, Ptolomy and Euclid and a host of other giants upon whose shoulders stood contemporaries such as Descartes, Newton and Einstein believed that the World was comprehensible. Had they not believed this, they might have abandoned their studies to simply accept superstition and malformed faith, returning to a life of nescient practice. It's a good thing for us that they described at least a starting point for conceptual physical unity to the tiniest, most fundamental things they could think of.
Atomic physics is a subject about powers, objects, forces, motion and change. It is a quintessential study of reality that can be both sensed and conceived if a concise, succinct, accurate, flexible, and dynamic language is shared among its proponents. Learning this language, the Mathematics of Theoretical Physics perhaps should be the primary goal of the physics student.
As Einstein did in his book, Relativity : the Special and General Theory, this course will advance the learner (and some teachers) in a "step-motherly" fashion so that "readers unfamiliar with physics may not feel like the wanderer who was unable to see the forest for the trees."
Imagine a young Pythagoras sitting cross-legged on a Samian beach with his new lyre. With the index finger of one hand he gently touches the midpoint of a string, while carefully plucking it with the thumbnail of his other hand. Does this have anything to do with atomic physics? The English chemist, John Newlands might have thought so.