14SiSilicon28.085[Ne] 3s² 3p²
metalloid

Silicon

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.

Electronic structure

A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.

Electrons by shell
Electron configuration
3s2
3p2

10 is the [Ne] core total across two shells.

Properties

At a glance

Atomic number
14
Atomic mass
28.085 u
Phase
Solid
Density
2.329 g/cm³
Melting point
1,687 K
Boiling point
3,538 K
First ionization energy
786.5 kJ/mol
Electronegativity
1.9
Electron affinity
134.0684 kJ/mol
Molar heat capacity
19.789 J/(mol·K)
Period
3
Appearance
crystalline, reflective with bluish-tinged faces

Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.

Keep exploring

Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.