Helium has an atomic number of 2, meaning each atom contains 2 protons in its nucleus.
The standard atomic weight of helium is 4.0026 u (unified atomic mass units).
Helium is classified as a noble gas.
Helium is a gas at 20 Β°C (68 Β°F).
The boiling point of helium is -268.93 Β°C / 4.222 K.
The density of helium is 1.64e-4 g/cmΒ³ (20Β°C).
The electron configuration of helium is 1s2.
Helium was discovered in 1895 by Sir William Ramsay; independently by Per Teodor Cleve and Nils Abraham Langlet.
Helium is a stable element with no naturally occurring radioactive isotopes.
No known biological role. Non-toxic.
Helium is used for: MRI cooling; NMR spectrometers; Balloons and airships; Arc welding; Deep-sea breathing mixtures.