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.
Quick Facts Pronunciation, Allotropes ...
Silicon, 00 Si Pronunciation Allotropes see Allotropes of silicon Appearance crystalline, reflective with bluish-tinged faces [ 28.084 , 28.086 ][1]
Group group 14 (carbon group) Period period 3 Block p-block Electron configuration [ Ne ] 3s2 3p2 Electrons per shell 2, 8, 4 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
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
1908
2102
2339
2636
3021
3537
Oxidation states −4, −3, −2, −1, 0,[2] +1,[3] +2, +3, +4 (an amphoteric oxide) Electronegativity Pauling scale: 1.90 Ionization energies 1st: 786.5 kJ/mol 2nd: 1577.1 kJ/mol 3rd: 3231.6 kJ/mol (more ) Atomic radius empirical: 111 pm Covalent radius 111 pm Van der Waals radius 210 pm Spectral lines of siliconNatural 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)[4] Band gap 1.12 eV (at 300 K) Magnetic ordering diamagnetic [5] Molar magnetic susceptibility − 3.9·10−6 cm3 /mol (298 K)[6] Young's modulus 130–188 GPa[7] Shear modulus 51–80 GPa[7] Bulk modulus 97.6 GPa[7] Poisson ratio 0.064–0.28[7] Mohs hardness 6.5 CAS Number 7440-21-3 Naming after Latin 'silex' or 'silicis', meaning flint Prediction Antoine Lavoisier (1787)Discovery and first isolationJöns Jacob Berzelius [8] [9] (1823)Named by Thomas Thomson (1817)
Main isotopes[10]
Decay
abun dance
half-life (t 1/2 )
mode
pro duct
28 Si
92.2%
stable
29 Si
4.7%
stable
30 Si
3.1%
stable
31 Si
trace
2.62 h
β−
31 P
32 Si
trace
153 y
β−
32 P
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Small grains of silicon because it has been crushed. This is not the silicon used in computers .
A thin cut of a large crystal of silicon that is very smooth. This is the type of silicon can be used in computers because it is very pure .
Silicon looks like a metal , but cannot do everything that a metal can, like conduct electricity well. Silicon is used a lot in today's computers and nearly every other electronic device as well. Germanium can also be used in computers, but silicon is much easier to find.
For example, all of the sand found at the beach is made of small cubes of silicon dioxide also known as silica . Glass is made by heating sand hot enough until it melts.[11] Glass made from silicon can be made in different colours by adding colouring compounds. Many rocks and minerals are composed of compounds of silicon and oxygen called silicates .