Silicon is the chemical element with atomic number 14 and is central to modern semiconductor technology.
Silicon is a metalloid with four valence electrons. Pure silicon is a semiconductor: its electrical conductivity lies between that of conductors and insulators, and it can be precisely changed by adding small amounts of other elements. This controlled process, called doping, enables transistors, diodes, and integrated circuits.
Silicon is abundant in Earth’s crust, although it is rarely found as a free element in nature. It commonly occurs in silicates and in silicon dioxide, the mineral compound found in quartz and many rocks. Silicon dioxide is also a major ingredient of ordinary glass.
The term Silicon Valley refers to California’s Santa Clara Valley and became associated with the region’s semiconductor and technology industries. Silicon and silicone are not the same: silicon is an element, while silicones are synthetic polymers containing silicon, oxygen, carbon, and hydrogen.