Silicon




 * Atomic Number:** 14
 * Atomic Weight:** 28.0855
 * Melting Point:** 1687 K (1414°C or 2577°F)
 * Boiling Point:** 3538 K (3265°C or 5909°F)
 * Density:** 2.3296 grams per cubic centimeter
 * Phase at Room Temperature:** Solid
 * Element Classification:** Semi-metal
 * Period Number:** 3 **Group Number:** 14 **Group Name:** none

Two allotropes of silicon exist at room temperature: amorphous and crystalline. Amorphous appears as a brown __powder__ while crystalline silicon has a metallic luster and a grayish color.

The element Silicon (Si) is not a mineral because it does not occur in nature. It is known as “the beauty element;" it might not be as popular as mineral celebrities like Calcium and Iron but it is for your health.

Silicon dioxide (SiO 2 ), silicon's most common compound, is the most abundant compound in the earth's crust.

Silicon is a metalloid, readily either donating or sharing its four outer electrons, allowing for many forms of chemical bonding. Even though it is relatively inert like carbon, silicon still reacts with halogens and dilute alkalis, but most acids (except for some hyper-reactive combinations of nitric acid and hydrofluoric acid ) have no known effect on it. However, having four bonding electrons gives it, like carbon, many opportunities to combine with other elements or compounds under the right circumstances.
 * __Chemical Characteristics__**


 * Distinctive characteristics of silicon**

1- It has the property that is characteristic __electrical insulator__ at low temperatures, semi-conductor in __degrees__ Aharah normal, and the connected increase when adding Daialh quantities of other items have. Note This property is mainly in the manufacture of small electronic chips Microchips upon which the computers are Responsible for the small size of computers at the present time.

2 - Department of Electrical kind made ​​of silicon less affected by __aging__ factors and factors of humidity, vibrations and __shocks__, which are made of the purest types of silicon.


 * Uses**

1 - it's used in the manufacture of electronic transistor and the cells 2 - it's used in the manufacture of cement and bricks 3 - it's used in the operations of agriculture without soil 4 - it's used in plastic surgery 5 - its the basis of the glass industry it is also used widely in all electronic devices like the computer automated

**History of Silicon**
Silicon was discovered by Jöns Jacob Berzelius, a Swedish chemist, in 1824 by heating chips of potassium in a silica container and then carefully washing away the residual by-products. Silicon is the seventh most abundant element in the universe and the second most abundant element in the earth's crust. Today, silicon is produced by heating sand (SiO 2 ) with carbon to temperatures approaching 2200°C. Two allotropes of silicon exist at room temperature: amorphous and crystalline. Amorphous appears as a brown __powder__ while crystalline silicon has a metallic luster and a grayish color. Single crystals of crystalline silicon can be grown with a process known as the Czochralski process. These crystals, when doped with elements such as boron, gallium, germanium, phosphorus or arsenic, are used in the manufacture of solid-state electronic devices, such as transistors, solar cells, rectifiers and microchips. Silicon dioxide (SiO 2 ), silicon's most common compound, is the most abundant compound in the earth's crust. It commonly takes the form of ordinary sand, but also exists as quartz, rock crystal, amethyst, agate, flint, jasper and opal. Silicon dioxide is extensively used in the manufacture of glass and bricks. Silica gel, a colloidal form of silicon dioxide, easily absorbs moisture and is used as a desiccant. Silicon forms other useful compounds. Silicon carbide (SiC) is nearly as hard as diamond and is used as an abrasive. Sodium silicate (Na 2 SiO 3 ), also known as water glass, is used in the production of soaps, adhesives and as an egg preservative. Silicon tetrachloride (SiCl 4 ) is used to create smoke screens. Silicon is also an important ingredient in silicone, a class of material that is used for such things as lubricants, polishing agents, electrical insulators and __medical__ implants.
 * USES**

Measured by mass, silicon makes up 27.7% of the Earth's crust and is the second most abundant element in the crust, with only oxygen having a greater abundance. Silicon is usually found in the form of complex silicate minerals, and less often as silicon dioxide (**silica**, a major component of common sand). Pure silicon crystals are very rarely found in nature. The silicate minerals —various minerals containing silicon, oxygen and reactive metals—account for 90% of the mass of the Earth's crust. This is due to the fact that at the high temperatures characteristic of formation of the inner solar system, silicon and oxygen have a great affinity for each other, forming networks of silicon and oxygen in chemical compounds of very low volatility. Since oxygen and silicon were the most common non-gaseous and non-metallic elements in the debris from supernova dust which formed the protoplanetary disk in the formation and evolution of the Solar System, they formed many complex silicates which accreted into larger rocky planetesimals that formed the terrestrial planets. Here, the reduced silicate mineral matrix entrapped the metals reactive enough to be oxidized (aluminum, calcium, sodium, potassium and magnesium). After loss of volatile gases, as well as carbon and sulfur via reaction with hydrogen, this silicate mixture of elements formed most of the Earth's crust. These silicates were of relatively low density with respect to iron, nickel, and other metals non-reactive to oxygen and thus a residuum of uncombined iron and nickel sank to the planet's core, leaving a thick mantle consisting mostly of magnesium and iron silicates above.
 * __Occurrence__**

Silicon is the 8th most abundant element in the universe. It is one of the most important ingredients for making steel. Silicon is used to make glass.

Silicon is commonly used for wristbands.

Silicon is mainly found in complex minerals and it also can be found in food.

**Silicon and hair:**
One positive thing about hair products that contain silicon is that it's cheap for the companies to use, so your shampoo and conditioner is cheap. It also leaves hair feeling "smooth". Unfortunately, Silicon based hair products don't promote hair growth or healthy hair growth. Silicon coats the hair shaft, not letting any product penetrate the hair strands. You CAN'T wash out silicone. It is not water soluble. So when you wash your hair, more and more just builds up. Eventually your hair just gets flat, and dull.