All practice pages/Interatomic theory/Elements
Element 14, a metalloid
The second most abundant element in the crust, the main ingredient of sand and rock, and the element computer chips are made from.
Period 3, group 14. The other metalloids are tinted, and every cell opens its own article.
Four valence electrons like carbon, so silicon forms four covalent bonds. Unlike carbon it rarely bonds to itself in long chains; instead it links through oxygen, Si-O-Si, in quartz, glass and the silicate minerals.
About 28% of the crust by mass, second only to oxygen, but never free: it is in quartz sand, clay, granite and nearly every rock-forming mineral, bound to oxygen.
Jöns Jacob Berzelius isolated it in 1824 by heating potassium fluorosilicate with potassium. The name comes from the Latin silex, flint, with the ending -on to match carbon and boron.
Ultra-pure silicon is the base of computer chips and most solar panels. Far more is used as sand and silicates in concrete, glass and ceramics. Silicon metal strengthens aluminum alloys, and silicones, polymers with a silicon-oxygen backbone, make sealants, bakeware, lubricants and medical implants.