neon

Neon (Ne) is the element with atomic number 10, symbol Ne. Its most common isotope has mass number 20, but 21 and 22 are also stable. It is the fifth most common element in the universe but rare on Earth. Its nuclei are synthesized by carbon burning and the alpha process, in stars and supernova. In sufficiently massive stars, a neon-burning shell forms during the asymptotic giant branch (AGB) phase.