10 Silicon Facts (Element Number 14 or Si)

Silicon is element number 14 on the periodic table, with the element symbol Si. Here is a collection of facts about this interesting and useful element: Silicon Fact Sheet Credit for discovering silicon is given to  Swedish chemist Jà ¶ns Jakob Berzelius, who reacted potassium fluorosilicate with potassium to produce amorphous silicon, which he named silicium, a name first proposed by Sir Humphry Davy in 1808. The name derives from the Latin words silex or silicis, which mean flint. Its probable English scientist Humphry Davy may have isolated impure silicon in 1808 and  French chemists Joseph L. Gay-Lussac and Louis Jacques Thà ©nard may have produced impure amorphous silicon in 1811. Berzelius is credited for the elements discovery because his sample was purified by repeatedly washing it, while earlier samples were impure.Scottish chemist Thomas Thomson named the element silicon in 1831, keeping part of the name Berzelius had given, but changing the ending of the name to -on because the element showed more similarities to boron and carbon than to the metals that had -ium names.Silicon is a metalloid, which means it has properties of both metals and nonmetals. Like other metalloids, silicon has different forms or allotropes. Amorphous silicon is usually seen as a gray powder, while crystalline silicon is a gray solid with a shiny, metallic appearance. Silicon conducts electricity better than nonmetals, yet not as well as metals. In other words, its a semiconductor. Silicon has a high thermal conductivity and conducts heat well.  Unlike metals, its brittle, and not malleable or ductile. Like carbon, it usually has a valence of 4 (tetravalent), but unlike carbon, silicon can also form five or six bonds.  Silicon is the second most abundant element on Earth by mass, making up over 27% of the crust. Its commonly encountered in silicate minerals, such as quartz and sand, but only rarely occurs as a free element. Its the 8th most abundant element in the universe, found at levels of about 650 parts per million. Its the principal element in a type of meteorite called aerolites.Silicon is needed for plant and animal life. Some aquatic organisms, such as diatoms, use the element to construct their skeletons. Humans need silicon for healthy skin, hair, nails, and bones, and to synthesize the proteins collagen and elastin. Dietary supplementation with silicon may increase bone density and reduce the risk of osteoporosis.Most silicon is used to produce the alloy ferrosilicon. Its used to produce steel. The element is purified to make semiconductors and other electronics. The compound silicon carbide is an important abrasive. Silicon dioxide is used to make glass. Because silicate minerals are common, silicon oxides form rocks and are used to make glass and ceramics.Like water (and unlike most chemicals), silicon has a higher density as a liquid than as a solid.Natural silicon consists of three stable isotopes: silicon-28, silicon-29, and silicon-30. Silicon-28 is the most abundant, accounting for 92.23% of the natural element. At least twenty radioisotopes are also known, with the most stable being silicon-32 , which has a half-life of 170 years.Miners, stone cutters, and people who live in sandy regions may inhale large quantities of silicon compounds and develop a lung disease called silicosis. Exposure to silicon may occur by inhalation, ingestion, skin contact, and eye contact. The Occupational Safety and Health Administration (OSHA) sets the legal limit for workplace exposure to silicon to  15  mg/m3  total exposure and 5  mg/m3  respiratory exposure for an 8-hour workday.Silicon is available at extremely high purity. Molten salt electrolysis of silica (silicon dioxide) or other silicon compounds can be used to obtain the element at 99.9% purity for use in semiconductors. The Siemens process is another method used to produce high purity silicon. This is a form of chemical vapor deposition where gaseous trichlorosilane is blown across a pure silicon rod to grow polycrystalline silicon (polysilicon) with a purity of 99.9999%.   Silicon Atomic Data Element Name: Silicon Element Symbol: Si Atomic Number: 14 Classification: metalloid (semimetal) Appearance: Hard gray  solid with a silver metallic luster. Atomic Weight: 28.0855 Melting Point:  1414  oC, 1687 K Boiling Point:  3265  oC, 3538 K Electron Configuration:  1s2  2s2  2p6  3s2  3p2 Density: 2.33  g/cm3 (as a solid near room temperature); 2.57 g/cm3 (as a liquid at the melting point) Oxidation States: 4, 3, 2, 1, -1, -2, -3, -4 Electronegativity: 1.90 on the Pauling scale Atomic Radius: 111 pm Crystal Structure: face-centered diamond cubic Heat of Fusion: 50.21 kJ/mol Heat of Vaporization: 383 kJ/mol Reference Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.