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Fluorine. cubic. Fluorine is a chemical element; it has symbol F and atomic number 9. It is the lightest halogen [note 1] and exists at standard conditions as pale yellow diatomic gas. Fluorine is extremely reactive as it reacts with all other elements except for the light inert gases.
Isotopes of fluorine (9F) ). Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and mononuclidic element. ; it has a half-life of 109.734 (8) min. All other fluorine isotopes have half-lives of less than a minute, and most of those less than a second.
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references. Fluoride (/ ˈflʊəraɪd, ˈflɔːr -/) [3] is an inorganic, monatomic anion of fluorine, with the chemical formula F−. (also written [F]−. ), whose salts are typically white or colorless.
Fluorine's chemistry is dominated by its strong tendency to gain an electron. It is the most electronegative element and elemental fluorine is a strong oxidant. The removal of an electron from a fluorine atom requires so much energy that no known reagents are known to oxidize fluorine to any positive oxidation state. [20]
Each distinct atomic number therefore corresponds to a class of atom: these classes are called the chemical elements. [5] 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.
In medical imaging, fluorine-18-labelled sodium fluoride (USP, sodium fluoride Na 18 F) is one of the oldest tracers used in positron emission tomography (PET), having been in use since the 1960s. [15] Relative to conventional bone scintigraphy carried out with gamma cameras or SPECT systems, PET offers more sensitivity and spatial resolution.
This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. For phosphorus (element 15) as an example, the concise form is [Ne] 3s 2 3p 3.
Infobox references. Calcium fluoride is the inorganic compound of the elements calcium and fluorine with the formula CaF 2. It is a white solid that is practically insoluble in water. It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities.