About

Silicon is a hard, brittle crystalline solid with a blue-gray metallic luster. It is the second most abundant element in the Earth's crust (after oxygen), mainly found in silicate minerals. As a semiconductor, it is the fundamental component of most modern electronics, including computer chips, transistors, and solar cells. It is also the basis for silicone polymers.

Atomic Properties

Atomic Number14

Atomic Weight28.085 u

Neutrons (common)14

Electron Configuration[Ne] 3s² 3p²

Full Configuration1s² 2s² 2p⁶ 3s² 3p²

Electrons per Shell2, 8, 4

Electronegativity1.9

Electron Affinity133.6 kJ/mol

Oxidation States+4, -4

Covalent Radius111 pm

Van der Waals Radius210 pm

Ionic Radius40 pm

Periodic Table Position

Group14

Period3

BlockP

Chemical SeriesMetalloids

Physical Properties

State at STPsolid

Appearancehard, brittle crystalline solid with a blue-gray metallic luster

Crystal Structurediamond cubic

Magnetic Orderingdiamagnetic

Speed of Sound2,200 m/s

Poisson Ratio0.22

Thermal Properties

Melting Point1,687 K

Boiling Point3,538 K

Thermal Expansion0 1/K

Thermal Conductivity149 W/(m·K)

Specific Heat0.705 J/(g·K)

Molar Heat20 J/(mol·K)

Heat of Fusion50.21 kJ/mol

Heat of Vaporization383 kJ/mol

Abundance

In Earth's Crust282,000 ppm

In Ocean2.2 ppm

In Solar System710 ppm

In Human Body260 ppm

In Universe700 ppm

Discovery

Discovered byJöns Jacob Berzelius

Discovery Year1,824

Occurrenceprimordial

CAS Number7440-21-3

Electron Configuration

Energy

↿⇂

↿

Isotopes of Silicon

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
²⁸Si	27.976926	92.223%	Stable	Stable
²⁹Si	28.976494	4.685%	Stable	Stable
³⁰Si	29.973770	3.092%	Stable	Stable
³²Si	31.974148	—	157 y	Beta Minus Decay

Interactive Visualization

Explore the 3D Bohr model of Silicon in our interactive viewer.

View 3D Model of Silicon