Helium (hài)?

lithium (Li)

beryllium (Be)

boron

Carbon (tàn)?

nitrogen

Oxygen (y m 4 ng)?

fluorine

Neon (n m: I)

Sodium (nà)?

Magnesium (mê I)?

aluminium (Al)

Silicon (guι)

phosphorus (P)

Sulfur (liú)?

Chlorine (lǜ)?

Argon (y)

Potassium (Ji m)?

calcium (Ca)

periodic table of chemical element

It is a list of chemical elements sorted by atomic number from small to large. The list is generally rectangular, and some elements have spaces in the period, so that elements with similar characteristics belong to the same family, such as halogen, alkali metal elements, rare gases (inert gases or rare gases), radioactive elements and so on. This makes the periodic table divided into seven main families, seven sub-families, zero families and eight families. Because the periodic table of elements can accurately predict the characteristics of various elements and their relationships, it is widely used in chemistry and other scientific fields as a very useful framework for analyzing chemical behavior.

Russian chemist Mendeleev invented the periodic table in 1869. Since then, 170 types of periodic tables have appeared, which can be summarized as short tables (represented by Mendeleev), long tables (represented by Werner type) and super-long tables (represented by Baltar type). Plane spiral table and circular table (represented by Damkoff type). Three-dimensional periodic table (represented by Lacey's cone-column three-dimensional table) and so on. Long periodic tables have long been used in primary schools.