Periodic table

In 1896 Russian scientists Dmitri Mendeleev created chemical periodic table, He was 63 elements according to the size of the atomic weight tabular form, align, put a similar chemical properties of the elements in the same line, the prototype of the periodic table are formed, the periodic table of atoms of element, element in descending order, the smallest ranked first. the form a transversely called a cycle, a list of called a clan.
Periodic table role
1. Inference properties: According to the same main group element nature alternation rule, the element f. Cl. Br. I can infer that At the nature of the nature.;
2. Characteristic comparison: By element cycle can compare the many properties. As the highest oxide acid and alkaline, hydride stability, atomic ions oxidizing, reducible, similar compounds of water-soluble, etc. This example many, students can oneself collects summary.
3. Looking for characteristic elements: According to the element cycle can be in periodic table in search for characteristic elements. The strongest elements such as nonmetal sex of the periodic table of the upper right shall be in, lively and metal will in table bottom, semiconductor elements in the middle will watch diagonal nearby, etc;