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Selenium is found in metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells.
This website is also cited in the CRC Handbook as source of Section 1, subsection Electron Configuration of Neutral Atoms in the Ground State. 91 Pa : [Rn] 5f 2 (3 H 4) 6d 7s 2; 92 U : [Rn] 5f 3 (4 I o 9/2) 6d 7s 2; 93 Np : [Rn] 5f 4 (5 I 4) 6d 7s 2; 103 Lr : [Rn] 5f 14 7s 2 7p 1 question-marked; 104 Rf : [Rn] 5f 14 6d 2 7s 2 question-marked
Noble gas configuration is the electron configuration of noble gases. The basis of all chemical reactions is the tendency of chemical elements to acquire stability . Main-group atoms generally obey the octet rule , while transition metals generally obey the 18-electron rule .
Selenocysteine is an analogue of the more common cysteine with selenium in place of the sulfur. Selenocysteine is present in several enzymes (for example glutathione peroxidases , tetraiodothyronine 5′ deiodinases , thioredoxin reductases , formate dehydrogenases , glycine reductases , selenophosphate synthetase 2 , methionine- R -sulfoxide ...
Selenium (Se) is an element in group 16, the chalcogens. Selenium is the first nonmetal in period 4, with properties similar to sulfur. Selenium is quite rare in pure form in nature, mostly being found in minerals such as pyrite, and even then it is quite rare. Selenium is necessary for humans in trace amounts, but is toxic in larger quantities.
Atomic number (Z): 34: Group: group 16 (chalcogens) Period: period 4: Block p-block Electron configuration [] 3d 10 4s 2 4pElectrons per shell: 2, 8, 18, 6: Physical properties; Phase at STP
Selenium in these reactions is almost always stereogenic, and the effect of epimerization at selenium (which is acid-catalyzed and occurs readily) on the elimination reaction is nearly unknown. In one example, separation and warming of selenoxides 1 and 2 revealed that 2 decomposes at 0 °C, while 1 , which presumably has more difficulty ...
Selenium was originally developed by Jason Huggins in 2004 as an internal tool at ThoughtWorks. [5] Huggins was later joined by other programmers and testers at ThoughtWorks, before Paul Hammant joined the team and steered the development of the second mode of operation that would later become "Selenium Remote Control" (RC).