Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical ...

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Chemical compounds are molecules made of atoms of different elements, while mixtures contain atoms of different elements not necessarily combined as molecules.

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118 chemical elements have been identified and named officially by IUPAC. A chemical element, often simply called an element, is a type of atom which has a ...

The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows ("periods") and columns ...

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A chiral molecule or ion exists in two stereoisomers that are mirror images of each other, called enantiomers; they are often distinguished as either "right- ...

A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. When chemical reactions occur, ...

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Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and ...

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Helium is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in ...