34
Selenium
Atomic Number34
Atomic Mass78.971 u
CategoryNonmetal
State at Room TempSolid
Year Discovered1817
About Selenium
Essential trace element important for thyroid function and antioxidant defense. Named after Selene, the Greek moon goddess. Used in glass production to remove green tint from iron impurities. Selenium rectifiers were used before silicon diodes. Brazil nuts are the richest food source. Toxic in large amounts, causing selenosis. Selenium sulfide is used in anti-dandruff shampoo.
More Nonmetals
1
Hydrogen
Lightest element. Makes up 75% of all normal matter by mass. Stars are mostly hy...
6
Carbon
The basis of all known life. Forms more compounds than any other element, over 1...
7
Nitrogen
Makes up 78% of Earths atmosphere. Essential for amino acids, DNA, and proteins....
8
Oxygen
The third most abundant element in the universe. Makes up 21% of Earths atmosphe...