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Oxygen. cubic (cP16) Oxygen is a chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other compounds.
O. have also been characterized, all short-lived. The longest-lived radioisotope is 15. O. with a half-life of 122.266 (43) s, while the shortest-lived isotope is the unbound 11. O. with a half-life of 198 (12) yoctoseconds, though half-lives have not been measured for the unbound heavy isotopes 27. O. and 28.
Oxygen compounds. Water (H 2 O) is the most familiar oxygen compound. The oxidation state of oxygen is −2 in almost all known compounds of oxygen. The oxidation state −1 is found in a few compounds such as peroxides. Compounds containing oxygen in other oxidation states are very uncommon: − 1⁄2 (superoxides), − 1⁄3 (ozonides), 0 ...
A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O 2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H 2 O).
Ozone (/ ˈoʊzoʊn /) (or trioxygen) is an inorganic molecule with the chemical formula O. 3. It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O. 2, breaking down in the lower atmosphere to O.
This is a list of chemical elements and their atomic properties, ordered by Atomic number.. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.
Molar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular, of a solute in a solution, in terms of amount of substance per unit volume of solution. In chemistry, the most commonly used unit for molarity is the number of moles per liter ...