The fact that all objects consist of elementary particles was assumed by scientists of Ancient Greece. But there was no way to prove this fact or to refute in those days. Yes, and about the properties of atoms in antiquity could only guess, based on their own observations of various substances.
It was possible to prove that all substances consist of elementary particles only in the 19th century and then indirectly. At the same time, physicists and chemists around the world tried to create a unified theory of elementary particles, describing their structure and explaining various properties, such as, for example, the charge of a nucleus.
The work of many scientists was devoted to the study of molecules, atoms and their structure. Physics gradually switched to the study of the microworld - elementary particles, their interaction and properties. Scientists became interested in what the atomic nucleus consists of , put forward hypotheses and try to prove them, at least indirectly.
As a result, a planetary model of the atomic structure proposed by Ernest Rutherford and Niels Bohr was adopted as the basic theory. According to this theory, the charge of the nucleus of any atom is positive, while negatively charged electrons rotate in its orbits, making the atom electrically neutral. Over time, this theory has been repeatedly confirmed by various kinds of experiments, starting with the experiments of one of its co-authors.
Modern nuclear physics considers the Rutherford-Bohr theory fundamental, all studies of atoms and their elements are based on it. On the other hand, most of the hypotheses that have appeared over the past 150 years have not been practically confirmed. It turns out that nuclear physics for the most part is theoretical in view of the extremely small sizes of the studied objects.
Of course, in the modern world it is much easier to determine the charge of an aluminum core, for example (or any other element) than in the 19th century, and even more so in ancient Greece. But making new discoveries in this field, scientists sometimes come to surprising conclusions. Trying to find a solution to one problem, particle physics is faced with new problems and paradoxes.
Initially, Rutherford's theory says that the chemical properties of a substance depend on what is the charge of the nucleus of its atom and, as a consequence, on the number of electrons rotating in its orbits. Modern chemistry and physics fully confirm this version. Despite the fact that the study of the structure of molecules was originally based on the simplest model - a hydrogen atom, whose core charge is 1, the theory fully applies to all elements of the periodic table, including
rare-earth metals and
radioactive substances obtained artificially at the end of the last millennium.
It is curious that long before the studies of Rutherford, an English chemist, a trained physician, William Poute, noted that the specific gravity of various substances is a multiple of this hydrogen index. He then suggested that all other elements simply consist of hydrogen at some simple level. That, for example, a nitrogen particle is 14 such minimal particles, oxygen is 16, etc. If we consider this theory globally in a modern interpretation, then in general it is true.