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Chemical substance – Form of matter; Inorganic compounds by element; List of alloys; List of alkanes; List of elements by name; List of minerals – List of minerals with Wikipedia articles; List of alchemical substances; Polyatomic ion – Ion containing two or more atoms; Exotic molecules – Atoms composed of exotic particles can form ...
In chemistry, the valence (US spelling) or valency (British spelling) of an atom is a measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Valence is generally understood to be the number of chemical bonds that each atom of a given chemical element typically forms.
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 ...
This makes it more difficult to combine the elements together. Compounds may be produced in a solid state reaction, by heating solids together, either in a vacuum or a gas. Common gases used include, oxygen, hydrogen, ammonia, chlorine, fluorine, hydrogen sulfide , or carbon disulfide.
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.
The main purpose of chemical nomenclature is to disambiguate the spoken or written names of chemical compounds: each name should refer to one compound. Secondarily, each compound should have only one name, although in some cases some alternative names are accepted. Preferably, the name should also represent the structure or chemistry of a compound.
The name of the cation (the unmodified element name for monatomic cations) comes first, followed by the name of the anion. [100] [101] For example, MgCl 2 is named magnesium chloride, and Na 2 SO 4 is named sodium sulfate (SO 2− 4, sulfate, is an example of a polyatomic ion).
In ionic compounds there arise characteristic distances between ion neighbours from which the spatial extension and the ionic radius of individual ions may be derived. The most common type of ionic bonding is seen in compounds of metals and nonmetals (except noble gases , which rarely form chemical compounds).