2 He 4.0026022

Helium

NOBLE GAS

Phase: Gas

Discovered: Pierre Janssen

Block: S

Summary

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 all the elements.

Appearance: colorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field

Source: Wikipedia

Physical Properties

Atomic Mass 4.0026022 u

Density 0.1786 g/cm³

Melting Point 0.95 K

Boiling Point 4.222 K

Molar Heat N/A

Electron Affinity -48 kJ/mol

Ionization Energies

1^st: 2372.3 kJ/mol

2^nd: 5250.5 kJ/mol