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A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
The chemical elements are what the periodic table classifies and organizes. Hydrogen is the element with atomic number 1; helium, atomic number 2; lithium, atomic number 3; and so on. Each of these names can be further abbreviated by a one- or two-letter chemical symbol; those for hydrogen, helium, and lithium are respectively H, He, and Li. [6]
This is a list of common chemical compounds with chemical formulae and CAS numbers, indexed by formula. This complements alternative listing at list of inorganic compounds . There is no complete list of chemical compounds since by nature the list would be infinite.
According to ASHRAE standard 34, the R-number of a chemical refrigerant is assigned systematically according to its molecular structure and has between two and four digits. If there are carbon -carbon multiple bonds , there are four digits in all: the number of these bonds is the first digit and the number of carbon atoms minus one (C-1) is next.
Chemical substance – Form of matter; List of alchemical substances; List of chemical elements; List of minerals – List of minerals with Wikipedia articles; List of named alloys; List of straight-chain alkanes; Polyatomic ion – Ion containing two or more atoms; Exotic molecule – a compound containing one or more exotic atoms
This is an index of lists of molecules (i.e. by year, number of atoms, etc.). Millions of molecules have existed in the universe since before the formation of Earth. Three of them, carbon dioxide, water and oxygen were necessary for the growth of life.
List of inorganic compounds. 18 languages. ... Although most compounds are referred to by their IUPAC systematic names (following IUPAC nomenclature), ...
This list is sorted by boiling point of gases in ascending order, but can be sorted on different values. "sub" and "triple" refer to the sublimation point and the triple point, which are given in the case of a substance that sublimes at 1 atm; "dec" refers to decomposition. "~" means approximately. Blue type items have an article available by ...