Editing Period 3 element (section)

=== Silicon ===
{{Main|Silicon}}
''Silicon'' (symbol '''Si''') is a [[carbon group|group 14]] [[metalloid]]. It is less reactive than its chemical analog [[carbon]], the nonmetal directly above it in the periodic table, but more reactive than [[germanium]], the metalloid directly below it in the table. Controversy about silicon's character dates from its discovery: silicon was first prepared and characterized in pure form in 1824, and given the name silicium (from {{langx|la|silicis}}, flints), with an '''-ium''' word-ending to suggest a metal. However, its final name, suggested in 1831, reflects the more chemically similar elements carbon and boron.

Silicon is the eighth most [[Abundance of the chemical elements|common element]] in the universe by mass, but very rarely occurs as the pure free element in nature. It is most widely distributed in [[dust]]s, [[sand]]s, [[Minor planet|planetoids]] and [[planets]] as various forms of [[silicon dioxide]] (silica) or [[silicate]]s. Over 90% of the Earth's crust is composed of [[silicate minerals]], making silicon the [[Abundance of elements in Earth's crust|second most abundant element]] in the Earth's crust (about 28% by mass) after [[oxygen]].<ref>Nave, R. [http://hyperphysics.phy-astr.gsu.edu/hbase/tables/elabund.html Abundances of the Elements in the Earth's Crust], Georgia State University</ref>

Most silicon is used commercially without being separated, and indeed often with little processing of compounds from nature. These include direct industrial building use of [[clay]]s, silica [[sand]] and [[stone]]. Silica is used in ceramic [[brick]]. Silicate goes into [[Portland cement]] for [[mortar (masonry)|mortar]] and [[stucco]], and combined with silica sand and [[gravel]], to make [[concrete]]. Silicates are also in whiteware [[ceramic]]s such as [[porcelain]], and in traditional [[quartz]]-based [[soda–lime glass]]. More modern silicon compounds such as [[silicon carbide]] form abrasives and high-strength ceramics. Silicon is the basis of the ubiquitous synthetic silicon-based polymers called [[silicone]]s.

Elemental silicon also has a large impact on the modern world economy. Although most free silicon is used in the steel refining, aluminum-casting, and fine chemical industries (often to make [[fumed silica]]), the relatively small portion of very highly purified silicon that is used in semiconductor electronics (< 10%) is perhaps even more critical. Because of wide use of silicon in [[integrated circuits]], the basis of most computers, a great deal of modern technology depends on it.