Periodic table of elements
The periodic table of chemical elements is a list of chemical elements sorted according to the number of nuclear charges of the elements from small to large. The list is generally rectangular, and there are spaces in some element periods, so that elements with similar characteristics are grouped in the same group, such as alkali metal elements, alkaline earth metals, halogen elements, rare gases, nonmetals, transition elements, etc. This makes element divisions formed in the periodic table and divided into seven main groups, seven subgroups, VIII groups, and 18 groups. Because of its ability to accurately predict the properties of various elements and their relationships, the periodic table is widely used in chemistry and other sciences as a useful framework for analyzing chemical behavior.