Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.Symbol: He
Atomic number: 2
Electron configuration: 1s2
Discovered: 1895
Atomic mass: 4.002602 ± 0.000002 u
Discoverers: Pierre Janssen, Norman Lockyer