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In humans, selenium is a trace element nutrient that functions as cofactor for reduction of antioxidant enzymes, such as glutathione peroxidases and certain forms of thioredoxin reductase found in animals and some plants (this enzyme occurs in all living organisms, but not all forms of it in plants require selenium).
Selenium Remote Control was a refactoring of Driven Selenium or Selenium B designed by Paul Hammant, credited with Jason as co-creator of Selenium. The original version directly launched a process for the browser in question, from the test language of Java, .NET, Python or Ruby.
In the periodic table of the elements, each column is a group. In chemistry, a group (also known as a family) [1] is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the 14 f-block columns, between groups 2 and 3, are not numbered.
Recognition status, as metalloids, of some elements in the p-block of the periodic table. Percentages are median appearance frequencies in the lists of metalloids. [n 2] The staircase-shaped line is a typical example of the arbitrary metal–nonmetal dividing line found on some periodic tables.
The nonmetallic character of selenium is shown by its brittleness [440] and the low electrical conductivity (~10 −9 to 10 −12 S•cm −1) of its highly purified form. [93] This is comparable to or less than that of bromine (7.95 × 10 –12 S•cm −1 ), [ 446 ] a nonmetal.
Selenium has a hexagonal polyatomic (CN 2) crystalline structure. It is a semiconductor with a band gap of 1.7 eV, and a photoconductor meaning its electrical conductivity increases a million-fold when illuminated. Selenium has a moderate ionisation energy (941.0 kJ/mol), high electron affinity (195 kJ/mol), and high electronegativity (2.55).
Of the group 7 elements, only manganese has a role in the human body. It is an essential trace nutrient, with the body containing approximately 10 milligrams at any given time. It is present as a coenzyme in biological processes that include macronutrient metabolism, bone formation, and free radical defense systems.