•Selenium (Greek selene,"moon"), symbol
Se, semimetallic element with an atomic
number of 34. Selenium is in group 16 (or VIa)
of the periodic table.
Selenium was discovered in 1817 by the Swedish chemist Baron
Jons Jakob Berzelius in a sulfuric acid residue. It was so called because it was found in association with tellurium (Latin tellus,"earth").
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