Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity.Symbol: B
Atomic number: 6
Electron configuration: [He] 2s2 2p2
Electrons per shell: 2,4
Atomic mass: 12.0107 ± 0.0008 u
Discovered: 3750 BC