Silicon (14)

Silicon is present in the sun and stars and is a principal component of a class of meteorites known as aerolites. Silicon makes up 25.7% of the earth's crust by weight, and is the second most abundant element, exceeded only by oxygen. It is found largely as silicon oxides such as sand (...silica), quartz, rock crystal, amethyst, agate, flint, jasper and opal. Silicon is found also in minerals such as asbestos, feldspar, clay and mica.

Silicon is important in plant and animal life. Diatoms in both fresh and salt water extract silica from the water to use as a component of their cell walls. Silicon is an important ingredient in steel. Silicon carbide is one of the most important abrasives. Workers in environments where silicaceous dust is breathed may develop a serious lung disease known as silicosis.

·         Name: Silicon

·         Symbol: Si

·         Atomic number: 14

·         Atomic weight: 28.0855

·         Standard state: solid at 298 K

·         CAS Registry ID: 7440-21-3

·         Group in periodic table: 14

·         Period in periodic table: 3

·         Block in periodic table: p-block

·         Color: dark grey with a bluish tinge

·         Classification: Semi-metallic

Historical information

Silicon was discovered by Jöns Jacob Berzelius at 1824 in Sweden. Origin of name: from the Latin word "silicis" meaning "flint".

Jöns Jacob Berzelius is generally credited with the discovery of silicon in 1824. Deville prepared crystalline silicon in 1854, a second allotropic form of the element.

Physical properties

Melting point: 1687 [or 1414 °C (2577 °F)] K
Boiling point: 3173 [or 2900 °C (5252 °F)] K
Density of solid: 2330 kg m-3

Orbital properties

Ground state electron configuration: [Ne].3s2.3p2
Shell structure: 2.8.4
Term symbol: 3P0

Isolation

There is normally no need to make silicon in the laboratory as it is readily available commercially. Silicon is readily available through the treatment of silica, SiO2, with pure graphite (as coke) in an electric furnace.

SiO2 + 2C → Si + 2CO

Under these conditions, silicon carbide, SiC, can form. However, provided the amount of SiO2 is kept high, silicon carbide may be eliminated.

2SiC + SiO2 → 3Si + 2CO

Very pure silicon can be made by the reaction of SiCl4 with hydrogen, followed by zone refining of the resultant silicon.

SiCl4 + 2H2 → Si River Valley 4-H

Interesting Facts:

1. About 26% of the earth's crust contains Silicon. This means that the element is a common element. Although it is common in nature, Silicon can also be produced commercially.

2. Meteorites known as aerolites are composed mostly of Silicone.

3. In nature, Silicon usually occurs as either an oxide or a silicate. It is not found unbound in nature.

4. In silicate form, Silicon is found in minerals like granite, feldspar, mica, clay and asbestos.

5. Silicon is used to make steel and electronic components.

6. When combined with oxygen, Silicon forms sand (silicon dioxide).

7. Silicon is used to make glass.

8. Silicon Valley is the nickname for a place in California that has many electronic and computer manufacturing companies. It is so named because Silicon is one of the materials used to make such computer and electronic products. Other countries including India, England, Mexico, and Germany also have areas which they call Silicon Valley for similar reasons.

9. The name Silicon comes from the Latin name "Silex".

10. Silicon dust can be dangerous. Workers who inhale the dust can develop a lung disease called silicosis.

11. Silicon also has uses in the plastic surgery industry. Silicon implants have been used by doctors to change the look of many parts of the body including the cheeks and chin.

12. Silicon has been used to make artificial heart valves.

13. Liquid Silicon can be used in retinal surgery.

14. A 2001 science fiction movie called Evolution dealt with the idea of Silicon based life forms taking over the Earth.

15. China is now the leading supplier of commercially produced Silicon. Russia, Norway, Brazil, and the United States all produce Silicon commercially.

16. Silicon is commercially produced using a procedure called "The Czochralski process". The process is named after Polish scientist Jan Czochralski who discovered the method in 1916 while experimenting with metals in his laboratory.

17. Some plants like rice need Silicon for their growth. Silicon has also been shown to help a plant's ability to fight pests and to survive a drought. It can also help to increase crop yields.

18. More than half of the Silicon used in the world is used to make car parts for the automotive industry. Over 55% of the Silicon used is dedicated for use in this manner.