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helium

Syllabification: he·li·um
Pronunciation: /ˈhēlēəm
 
/

Definition of helium in English:

noun

The chemical element of atomic number 2, an inert gas that is the lightest member of the noble gas series. (Symbol: He)

Helium occurs in traces in air and more abundantly in natural gas deposits. It is used as a lifting gas for balloons and airships, and liquid helium (boiling point: 4.2 kelvins, 268.9°C) is used as a coolant. Helium is produced in stars as the main product of the thermonuclear fusion of hydrogen and is the second most abundant element in the universe after hydrogen

Example sentences
  • Other light elements that are commonly proposed for the outer core are silicon, carbon, helium, and nitrogen.
  • Ramsay realized that argon and helium might be members of a hitherto unsuspected new group in the Periodic Table.
  • Cool the detectors with liquid nitrogen instead of solid hydrogen or liquid helium.

Origin

late 19th century: modern Latin, from Greek hēlios 'sun', because its existence was inferred from an emission line in the sun's spectrum.

Definition of helium in:

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