Silicon
Silicon is a chemical element. Its atomic number is 14 on the periodic table. Its symbol is Si. It is a hard, brittle crystalline solid. It is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table.
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General properties | |||||||||||||||||||||||||||||||
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Pronunciation | /ˈsɪlɪkən/ | ||||||||||||||||||||||||||||||
Appearance | crystalline, reflective with bluish-tinged faces | ||||||||||||||||||||||||||||||
Standard atomic weight (Ar, standard) | [28.084, 28.086] conventional: 28.085 | ||||||||||||||||||||||||||||||
Silicon in the periodic table | |||||||||||||||||||||||||||||||
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Atomic number (Z) | 14 | ||||||||||||||||||||||||||||||
Group | group 14 (carbon group) | ||||||||||||||||||||||||||||||
Period | period 3 | ||||||||||||||||||||||||||||||
Block | p-block | ||||||||||||||||||||||||||||||
Electron configuration | [Ne] 3s2 3p2 | ||||||||||||||||||||||||||||||
Electrons per shell | 2, 8, 4 | ||||||||||||||||||||||||||||||
Physical properties | |||||||||||||||||||||||||||||||
Phase at STP | solid | ||||||||||||||||||||||||||||||
Melting point | 1687 K (1414 °C, 2577 °F) | ||||||||||||||||||||||||||||||
Boiling point | 3538 K (3265 °C, 5909 °F) | ||||||||||||||||||||||||||||||
Density (near r.t.) | 2.3290 g/cm3 | ||||||||||||||||||||||||||||||
when liquid (at m.p.) | 2.57 g/cm3 | ||||||||||||||||||||||||||||||
Heat of fusion | 50.21 kJ/mol | ||||||||||||||||||||||||||||||
Heat of vaporization | 383 kJ/mol | ||||||||||||||||||||||||||||||
Molar heat capacity | 19.789 J/(mol·K) | ||||||||||||||||||||||||||||||
Vapor pressure
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Atomic properties | |||||||||||||||||||||||||||||||
Oxidation states | −4, −3, −2, −1, +1[1] +2, +3, +4 (an amphoteric oxide) | ||||||||||||||||||||||||||||||
Electronegativity | Pauling scale: 1.90 | ||||||||||||||||||||||||||||||
Ionization energies |
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Atomic radius | empirical: 111 pm | ||||||||||||||||||||||||||||||
Covalent radius | 111 pm | ||||||||||||||||||||||||||||||
Van der Waals radius | 210 pm | ||||||||||||||||||||||||||||||
Spectral lines of silicon | |||||||||||||||||||||||||||||||
Other properties | |||||||||||||||||||||||||||||||
Natural occurrence | primordial | ||||||||||||||||||||||||||||||
Crystal structure | face-centered diamond-cubic | ||||||||||||||||||||||||||||||
Speed of sound thin rod | 8433 m/s (at 20 °C) | ||||||||||||||||||||||||||||||
Thermal expansion | 2.6 µm/(m·K) (at 25 °C) | ||||||||||||||||||||||||||||||
Thermal conductivity | 149 W/(m·K) | ||||||||||||||||||||||||||||||
Electrical resistivity | 2.3×103 Ω·m (at 20 °C)[2] | ||||||||||||||||||||||||||||||
Band gap | 1.12 eV (at 300 K) | ||||||||||||||||||||||||||||||
Magnetic ordering | diamagnetic[3] | ||||||||||||||||||||||||||||||
Magnetic susceptibility | −3.9·10−6 cm3/mol (298 K)[4] | ||||||||||||||||||||||||||||||
Young's modulus | 130–188 GPa[5] | ||||||||||||||||||||||||||||||
Shear modulus | 51–80 GPa[5] | ||||||||||||||||||||||||||||||
Bulk modulus | 97.6 GPa[5] | ||||||||||||||||||||||||||||||
Poisson ratio | 0.064–0.28[5] | ||||||||||||||||||||||||||||||
Mohs hardness | 6.5 | ||||||||||||||||||||||||||||||
CAS Number | 7440-21-3 | ||||||||||||||||||||||||||||||
History | |||||||||||||||||||||||||||||||
Naming | after Latin 'silex' or 'silicis', meaning flint | ||||||||||||||||||||||||||||||
Prediction | Antoine Lavoisier (1787) | ||||||||||||||||||||||||||||||
Discovery and first isolation | Jöns Jacob Berzelius[6][7] (1823) | ||||||||||||||||||||||||||||||
Named by | Thomas Thomson (1817) | ||||||||||||||||||||||||||||||
Main isotopes of silicon | |||||||||||||||||||||||||||||||
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Silicon looks like a metal, but does not do everything a metal does, like conduct electricity very easily. Silicon is used as a great deal in today's computers and virtually every electronic device. Germanium can also be used in computers, but silicon is easier to find.
There is a lot of silicon on the Earth. At the beach, there is silicon in the form of sand. Sand is a compound of silicon known as silicon dioxide or silica. Glass is made by heating sand (or silicon dioxide) hot enough.[8] The glass can have different colours by adding coloured compounds. Silicon also makes up a lot of different rocks and minerals, and they are known as silicates.
Silicon in computersEdit
Silicon is a semiconductor, and much used in computers. A super-pure isotope of silicon, silicon-28, can now be made 40 times more pure than before. It is very important for the next big development in computers. This stores "qubits" in atoms of another element, like phosphorous, embedded in a tiny layer of ultra-pure silicon-28. These qubits can simultaneously encode a one and a zero, for incredibly fast and complex calculations.[9]
Related pagesEdit
ReferencesEdit
- ↑ Ram, R. S.; et al. (1998). "Fourier Transform Emission Spectroscopy of the A2D–X2P Transition of SiH and SiD" (PDF). J. Mol. Spectr. 190: 341–352. PMID 9668026.
- ↑ Eranna, Golla (2014). Crystal Growth and Evaluation of Silicon for VLSI and ULSI. CRC Press. p. 7. ISBN 978-1-4822-3281-3.
- ↑ Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
- ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
- ↑ 5.0 5.1 5.2 5.3 Hopcroft, Matthew A.; Nix, William D.; Kenny, Thomas W. (2010). "What is the Young's Modulus of Silicon?". Journal of Microelectromechanical Systems. 19 (2): 229. doi:10.1109/JMEMS.2009.2039697.
- ↑ Weeks, Mary Elvira (1932). "The discovery of the elements: XII. Other elements isolated with the aid of potassium and sodium: beryllium, boron, silicon, and aluminum". Journal of Chemical Education. 9 (8): 1386–1412. Bibcode:1932JChEd...9.1386W. doi:10.1021/ed009p1386.
- ↑ Voronkov, M. G. (2007). "Silicon era". Russian Journal of Applied Chemistry. 80 (12): 2190. doi:10.1134/S1070427207120397.
- ↑ "Glass Crusher Machines". www.qcr.co.uk. Retrieved 24 May 2016.
- ↑ Webb, Jonathan 2014. Purer-than-pure silicon solves problem for quantum tech. BBC News Science & Environment [1]