Overview

Helium is an inert, colorless, odorless noble gas with two protons and two electrons and extremely low boiling point.

Properties

It has very low density, high thermal conductivity and remains liquid at temperatures near absolute zero.

Occurrence and Uses

Found in natural gas deposits and used for MRI cryogenics, gas chromatography and as a lifting gas in controlled applications.

Isotopes and Safety

Stable isotopes He 3 and He 4 exist; helium is nonreactive and poses asphyxiation risk in confined spaces if it displaces oxygen.