helium

Definition

The second-lightest chemical element (symbol He), with an atomic number of 2 and atomic weight of 4.002602, a colorless, odorless and inert noble gas.

Etymology

From New Latin helium, from Ancient Greek ἥλιος (hḗlios, “sun”) (because its presence was first theorised in the Sun's atmosphere) with the suffix + -ium. Probably coined by Norman Lockyer. This suffix is unusual, because it is usually used only for metallic elements. It is likely that Lockyer, being an astronomer, was unaware of the usual chemical conventions.

Example Sentences

• "It was an enormous balloon filled with helium, that elemental gas forged from hydrogen in the nuclear furnace of the stars."