THE PERIODIC TABLE OF CHEMICAL ELEMENTS AND THE PROBLEM OF ITS JUSTIFICATION

The article considers five stages in the history of the discovery and attempts to substantiate Mendeleev’s periodic system of chemical elements. The first stage consists in the accumulation, systematic analysis of extensive empirical material and in the direct establishment of the periodic law of chemical elements by Mendeleev. At the second stage, attempts were made to atomic-electronic explanation of the periodicity of the physical and chemical properties of elements on the basis of quantum mechanics and the Pauli principle. The third stage is associated with the development of nuclear physics, as well as with the development of such chemical methods as radiochemical analysis, the chromatographic method of color, etc. At the fourth stage, a solution to the problem was proposed on the basis of group theory in the quantum mechanical understanding. The fifth stage is based on the relational substantiation of the periodic system of chemical elements of the Mendeleev’s table, corresponding to the method of describing hadrons.