2He
Helium
헬륨 · ヘリウム
Noble gas
Atomic number2
ElementHe — Helium
Atomic mass4.0026
CategoryNoble gas
Group18
Period1
Electron config1s2
Shells2
State (RT)Gas
Melting ptNo data
Boiling pt-269°C
Discovered1868
Main usesBalloons, cryogenic cooling, MRI
2