ABSTRACT
The Periodic Law (PL) establishes that the chemical and physical properties of the elements and their combinations are a periodic function of the atomic number of the element. The evolution of the discovery of elements with time followed several methods: blowlamp, Lavoisier’s theory of combustion, electrolysis, spectroscopy, Mendeleev’s Periodic Law (PL), fractional distillation, radioactivity, particle accelerators, etc. The important PL fact is that this dependence implies a certain periodicity, which shows in the periodic repetition of the characteristic properties: the elements with atomic numbers Z = 2, 10, 18, 36, 54, 86 and 118 are all chemically inert elements. The information could be attributed to little precise values of the corresponding magnitudes, and to the fact that the properties of the elements are not strictly those of the atom but the ones of the corresponding net, which typically does not repeat for the elements belonging to the same period.
