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Concept information

astrochemistry > chemical element (interstellar, circumstellar, or planetary)

Terme préférentiel

chemical element (interstellar, circumstellar, or planetary)  

Définition(s)

  • A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler substances by any chemical reaction. The number of protons in the nucleus is the defining property of an element, and is referred to as its atomic number (represented by the symbol Z) – all atoms with the same atomic number are atoms of the same element. Almost all of the baryonic matter of the universe is composed of chemical elements (among rare exceptions are neutron stars). When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds. Only a minority of elements, such as silver and gold, are found uncombined as relatively pure native element minerals. Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. Air is primarily a mixture of the elements nitrogen, oxygen, and argon, though it does contain compounds including carbon dioxide and water. (Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/wiki/Chemical_element)

Concept(s) générique(s)

URI

http://data.loterre.fr/ark:/67375/MDL-N06C8WKZ-5

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RDF/XML TURTLE JSON-LD Dernière modif. 28/09/2022