14
Si
Silicon
28.085
284
#14

Silicon

metalloid· Solid·28.085 u

Silicon is a chemical element with symbol Si and atomic number 14. It is a tetravalent metalloid, more reactive than germanium, the metalloid directly below it in the table. Controversy about silicon's character dates to its discovery.

Identity

Symbol
Si
Atomic Number
14
Atomic Mass
28.085 u
Category
metalloid
Block
p-block
Period
3
Group
14
Appearance
crystalline, reflective with bluish-tinged faces
Year Discovered
1823 CE
Discovered By
Jöns Jacob Berzelius
Named By
Thomas Thomson (chemist)

Electrons

Configuration
[Ne] 3s2 3p2
Full Configuration
1s2 2s2 2p6 3s2 3p2
Shells
2, 8, 4
Electronegativity
1.9
Electron Affinity
134.0684
Oxidation States
+4, +2, -4
Ionization Energies
786.5, 1577.1, 3231.6, 4355.5, 16091 … +9 more

Physical Properties

Silicon
State at
Solid
Melting Point
1687
Boiling Point
3538
Density
2.329
Molar Heat
19.789 J/(mol·K)
Crystal Structure
Diamond Cubic
Magnetic Ordering
Diamagnetic

Mechanical

Atomic Radius
111 pm
Covalent Radius
111 pm
Van der Waals
210 pm
Mohs Hardness
6.5
Brinell Hardness
9600 MPa MPa
Bulk Modulus
100 GPa GPa
Shear Modulus
52 GPa GPa
Young's Modulus
47 GPa GPa

Thermal & Electrical

Thermal Conductivity
149 W/(m K) W/(m·K)
Electrical Conductivity
0.001 MS/m S/m
Specific Heat
705 J/(kg K) J/(g·K)
Heat of Vaporization
359 kJ/mol kJ/mol
Heat of Fusion
50.2 kJ/mol kJ/mol

Abundance

Universe
650 ppm
Sun
900 ppm
Meteorite
17.0%
Earth's Crust
2.329 ppm
Ocean
2.2 ppm
Human Body
20 ppm