Silicon

Silicon 28.0855(3)   Si 14 1s22s22p63s23p2 [ ? ] Metalloid: Properties: In crystalline form, grayish metallic luster. Relatively inert chemically. Uses: Concrete, glass, refractories, ceramics, semiconductors.

Silicon is a chemical element, having the chemical symbol Si. Its atomic number (the number of protons) is 14. It has a standard atomic weight of 28.0855 g•mol ⁻¹, and is typically found as a solid in its various forms as silicon dioxide, silica and silicates.

Silicon is considered a member of the "Metalloid" class of element. At a pressure of 101.325 kPa, it has a boiling point 3,265 °C, and a melting point of 1,414 °C. In Earth's crust, silicon is the second most abundant element after oxygen, being about 28% of the crust by mass. Silicon has a density of 2.33 g/cc.