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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.
Positron emission tomography (PET) [1] is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption. Different tracers are used for various imaging ...
Phases of fluorine. Henri Moissan 's 1892 record of fluorine gas color, viewed end-on in a 5‑m tube. Air (1) is on the left, fluorine (2) is in the middle, chlorine (3) is on the right. 2) that are gaseous at room temperature with a density about 1.3 times that of air. [1][note 1] Though sometimes cited as yellow-green, pure fluorine gas is ...
Fluorine forms compounds with all elements except neon and helium. In particular, it forms binary compounds , named fluorides , with all said elements except argon . All of the elements up to einsteinium , element 99, have been checked except for astatine and francium , [ 24 ] and fluorine is also known to form compounds with mendelevium ...
Fluorine biology is also relevant to a number of cutting-edge technologies. PFCs (perfluorocarbons) are capable of holding enough oxygen to support human liquid breathing. Organofluorine in the form of its radioisotope 18 F is also at the heart of a modern medical imaging technique known as positron emission tomography (PET).
Fluorine is a relatively new element in human applications. In ancient times, only minor uses of fluorine-containing minerals existed. The industrial use of fluorite, fluorine's source mineral, was first described by early scientist Georgius Agricola in the 16th century, in the context of smelting. The name "fluorite" (and later "fluorine ...
Fluorene / ˈflʊəriːn /, or 9H-fluorene is an organic compound with the formula (C 6 H 4) 2 CH 2. It forms white crystals that exhibit a characteristic, aromatic odor similar to that of naphthalene. Despite its name, it does not contain the element fluorine, but rather it comes from the violet fluorescence it exhibits.
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.