14
Si
Silicon
28.085
Silicon (Si)
MetalloidGroup 14Period 3p-block-block
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.
Latin name: Silicium
Atomic Number
14
Atomic Mass
28.085 g/mol
Phase (STP)
Solid
Electron Config.
[Ne] 3s² 3p²
General
SymbolSi
Atomic Number14
Atomic Mass28.085 g/mol
CategoryMetalloid
Group14
Period3
Blockp-block
Electron Configuration[Ne] 3s² 3p²
Valence Electrons4
ColourCrystalline, reflective with bluish-tinged faces
Appearancecrystalline, reflective with bluish-tinged faces
CAS NumberCAS7440-21-3
Physical Properties
Phase (STP)Solid
Density2.3296 g/cm³
Melting Point1413.85°C · 2576.93°F · 1687.00 K
Boiling Point3264.85°C · 5908.73°F · 3538.00 K
Atomic Properties
Atomic Radius111 pm
Covalent Radius111 pm
Van der Waals Radius210 pm
Electronegativity1.9 Pauling
Ionization Energy787 kJ/mol
Electron Affinity133.6 kJ/mol
Oxidation States-4, -3, -2, -1, +1, +2, +3, +4
Ion ChargeSi⁴⁺/Si⁴⁻
Thermodynamic
Molar Heat19.789 J/(mol·K)
Thermal Conductivity150 W/(m·K)
Electromagnetic
Electrical TypeSemiconductor
Crystal Structure
Crystal StructureDiamond cubic
Mechanical Properties
Mohs Hardness6.5
Abundance
In Universe0.0700%
In Sun0.0900%
In Earth's Crust27.0000%
In Oceans0.0002%
In Humans0.0026%
In Meteorites14.0000%
Discovery & History
Discovery Year1824
Discovered ByJöns Jacob Berzelius
Named ByThomas Thomson (chemist)
Isotopes of Silicon
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Si-28 | 92.223% | Stable | — |
| Si-29 | 4.685% | Stable | — |
| Si-30 | 3.092% | Stable | — |
| Si-32 | — | 153 years | β⁻ |