It provides clues to predict the structure and properties of new elements. Periodic law and periodic table of elements are important tools in many departments of natural science, first of all, chemistry, physics, biology, geochemistry and so on.
Philosophically, the periodic law of elements reveals the fact that the properties of elements change periodically due to the increase of nuclear charge of elements, and strongly demonstrates the regularity of qualitative change caused by quantitative change of things from natural science.
The periodic table of elements is the concrete embodiment of the periodic law, which brings elements into a system, reflects the internal relationship between elements and breaks the metaphysical view that elements are isolated from each other. By studying the periodic law and the periodic table of elements, we can deepen our understanding of the law of unity of opposites in the material world.
Extended data:
periodic law
Elements show periodicity in various physical properties, for example, with the increase of the number of atoms of elements, the atomic volume shows obvious periodicity. In terms of chemical properties, the valence of elements, electronegativity, activity of metals and nonmetals, acidity and alkalinity changes of oxides and hydroxides, and changes of metals and nonmetals also have obvious periodicity.
Specifically: in the same period, the number of electron layers outside the nucleus is the same; In the same family, the number of extranuclear electrons is the same (except the first week). In the same cycle, these attributes are gradually changing, and in the next cycle, the attributes of the same family elements in the previous cycle are repeated.