Science Education Home Home Teachers Students Games Videos VA SOL Programs

It's Elemental

The Element Silicon

[Click for Isotope Data]


14 Si Silicon 28.0855

Atomic Number: 14

Atomic Weight: 28.0855

Melting Point: 1687 K (1414°C or 2577°F)

Boiling Point: 3538 K (3265°C or 5909°F)

Density: 2.3296 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Semi-metal

Period Number: 3

Group Number: 14

Group Name: none

What's in a name? From the Latin word for flint, silex.

Say what? Silicon is pronounced as SIL-ee-ken.

History and Uses:

Silicon was discovered by Jöns Jacob Berzelius, a Swedish chemist, in 1824 by heating chips of potassium in a silica container and then carefully washing away the residual by-products. Silicon is the seventh most abundant element in the universe and the second most abundant element in the earth's crust. Today, silicon is produced by heating sand (SiO2) with carbon to temperatures approaching 2200°C.

Two allotropes of silicon exist at room temperature: amorphous and crystalline. Amorphous appears as a brown powder while crystalline silicon has a metallic luster and a grayish color. Single crystals of crystalline silicon can be grown with a process known as the Czochralski process. These crystals, when doped with elements such as boron, gallium, germanium, phosphorus or arsenic, are used in the manufacture of solid-state electronic devices, such as transistors, solar cells, rectifiers and microchips.

Silicon dioxide (SiO2), silicon's most common compound, is the most abundant compound in the earth's crust. It commonly takes the form of ordinary sand, but also exists as quartz, rock crystal, amethyst, agate, flint, jasper and opal. Silicon dioxide is extensively used in the manufacture of glass and bricks. Silica gel, a colloidal form of silicon dioxide, easily absorbs moisture and is used as a desiccant.

Silicon forms other useful compounds. Silicon carbide (SiC) is nearly as hard as diamond and is used as an abrasive. Sodium silicate (Na2SiO3), also known as water glass, is used in the production of soaps, adhesives and as an egg preservative. Silicon tetrachloride (SiCl4) is used to create smoke screens. Silicon is also an important ingredient in silicone, a class of material that is used for such things as lubricants, polishing agents, electrical insulators and medical implants.

Estimated Crustal Abundance: 2.82×105 milligrams per kilogram

Estimated Oceanic Abundance: 2.2 milligrams per liter

Number of Stable Isotopes: 3 (View all isotope data)

Ionization Energy: 8.152 eV

Oxidation States: +4, +2, -4

Electron Shell Configuration:


2s2   2p6

3s2   3p2

Citation and linking information

For questions about this page, please contact Steve Gagnon.