The structure of the atom was of interest to scientists long before its existence was scientifically proven. Thousands of years ago, Democritus, the ancient Greek philosopher and sage, suggested that any substance consists of the smallest particles. And it was he who first used the word "atom." After his death, a group of Greek philosophers arose, whose members tried to develop his views. They were called atomists. All these views were expressed by the Roman Lucretius Car in his famous work "On the nature of things." However, in later times, until the beginning of the Renaissance, the views of another Greek sage, Aristotle, who categorically denied the existence of atoms, prevailed.
The first to attempt to revive the teachings of Democritus was the Englishman Boyle, who substantiated his theory of "indivisible particles." Newton echoed him. However, Dalton, a mathematics teacher, scientifically substantiated this teaching. Carrying out experiments with gases, he noticed that the ratio of those hydrogen and oxygen particles that participated in the chemical reaction always corresponds to a certain proportion. The latter, as a rule, are a ratio of small numbers. This made it possible for the English mathematics teacher to formulate his law of “multiple ratios,” and eventually the law of “constant relations,” based on which, in each chemical compound, the mass ratio of the starting materials is always the same. His research was continued by Berzellius and Avogadro.
The fact that the structure of the atom is quite complex was proved by physicists a century ago. Contributions to such a great discovery were made by: Thomson, who proved the existence of cathode rays, Skladovskaya-Curie and her husband Pierre Curie, who discovered the natural radioactivity of substances, Rutherford, who stated that there was a positively charged nucleus in the center of the atom and the possibility of artificial transformation of one element into another, Chadwick, who discovered the presence of neutral elements, or neutrons. The structure of the atom was first seriously studied by Thompson, who discovered the electron in 1897. He was able to prove the existence of even more microscopic bodies. Thanks to his work, the structure of the atom has become largely understandable. He discovered that this particle is represented by a spherical distribution of positive charges, which are fully compensated by negative ones. For this reason, an atom is electrically neutral.
As a result of a number of studies conducted by these and other scientists, it was found that the atom is not a homogeneous body, but consists of particles such as neutrons, protons and electrons.
There are as many protons in the nucleus of an atom as there are electrons in its shell, in addition, the number of protons corresponds to the number of the element in the periodic table. The masses of the proton and neutron are almost identical. These elements are held in the nucleus of the atom by special forces, which are also called nuclear; these forces are very powerful, but act at ultrashort distances, while many times exceeding the repulsive forces of particles. The weight of the electrons is very small. Almost the entire mass of an atom lies in its nucleus; the structure of the nucleus of an atom includes neutrons and protons. The properties of this part of it are determined by its main components mentioned above. Among atoms there are so-called isotones. These particles of the same substance have different masses due to the fact that the number of their neutrons can vary. The number of their protons, however, is always the same. For example, the structure of a carbon atom usually implies the presence of six positively charged particles and six neutral particles in its core — only 12, that is, the so-called mass number of carbon is most often 12. However, there are also isotopes of this element in which the number of protons stably corresponds to 6, and the number of neutrons may vary.
The shell of an atom is a rather complex system. It consists of various subshells with different energy levels, which, in turn, are divided into sublevels, and sublevels - into orbitals. The latter vary in shape and size.