<Tr> <Td_colspan="2"> <Ul> <Li> view </Li> <Li> talk </Li> <Li> </Li> </Ul> references in Wikidata </Td> </Tr> <Ul> <Li> view </Li> <Li> talk </Li> <Li> </Li> </Ul> <P> Silicon is a chemical element with symbol Si and atomic number 14 . A hard and brittle crystalline solid with a blue - grey metallic lustre, it is a tetravalent metalloid and semiconductor . It is a member of group 14 in the periodic table, along with carbon above it and germanium, tin, and lead below . It is rather unreactive, though less so than germanium, and has a very large chemical affinity for oxygen; as such, it was first prepared and characterized in pure form only in 1823 by Jöns Jakob Berzelius . </P> <P> Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust . It is most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates . Over 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust (about 28% by mass) after oxygen . </P>

When was silicon added to the periodic table