For all metals, their oxides and hydroxides are known, and d-elements have different oxidation states, so they form many oxides and hydroxides. The properties of these oxides and hydroxides depend on the position of the metal in the periodic system, on its activity and the oxidation state of the metal. Thus, all metals form salt-forming oxides. It is known that the more pronounced the metallic properties, the stronger the basic properties of oxides and hydroxides. For s- and p-elements, from left to right along the period, the metallic properties decrease, and hence the basic properties of metal oxides and hydroxides. In the IA group, the atomic radii increase from top to bottom, and cations are formed when electrons are donated from the outer level. Naturally, the oxidation state of these elements does not change, and the basic character of the oxides is enhanced. If we consider the change in the properties of the oxides of elements over the period using the example of period 3 elements, then it should be noted that the number of energy levels in the atoms of these elements is the same, but the oxidation state changes, that is, it increases, and the ion radius decreases, therefore, the nature of the oxides changes from the main one through amphoteric to acidic