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Helium

Helium is the second most abundant substance in the universe – Hydrogen being the most abundant.

 

 

Basic Information

Discovery of Helium

Sources of Helium

Uses of Helium

Liquid Helium in Superconductors

Use of Helium by Divers

Helium in Balloons and Airships

Helium’s Cell Structure

Absorption Lines of Helium

Emission Lines of Helium

 

Hydrogen.gifHydrogen.png

 

 

 

 

Helium (from the Greek helios meaning Sun)

 

 

Orion Nebula.png Classification: Non-metallic

Atomic Mass: 1.00794 g/mol

Density: 0.08988g/cm3

Colour: None

Boiling Point: 20.268K (-252.87°C

Melting Point: 14.01K (-259.14°C)

Critical Temperature: 33K (-240°C)

The outreaching wave is called the prominence and is composed of ionized Helium that is about 60,000 degrees Kelvin. (Image from NASA)

 

 

Discovery

Discovery: Helium was first detected by French astronomer Pierre Janssen during a total solar eclipse in Guntur, India on the 18th of August 1868 using spectroscopy. It was evident as a bright yellow line (a wavelength of 587.49 nanometres) in the spectrum of the Chromosphere of the Sun but it was assumed that this line was produced by sodium which produces similar yellow lines. But it was

 

On the 20th of October 1868 English astronomer Norman Lockyer observed the same line and concluded that it was produced by an element in the sun that was as yet un-discovered on earth. Lockyer and English chemist Edward Frankland named the element after the Greek word for the Sun (helios).

 

Helium was not isolated on earth until the 26th of March 1895 when a Scottish chemist Sir William Ramsey isolated samples whilst attempting isolate argon. The samples were confirmed to be Helium by Lockyer and English physicist William Crookes. In the same year helium had independently been isolated by Swedish chemist Per Teodor Cleve and Abraham Langle producing enough samples to accurately determine its atomic weight.

 

Sources

Helium is produced in vast quantities in space through nuclear fussion of hydrogen atoms within stars. On earth Commercially helium is mainly collected from natural gas deposits in Texas, U.S, Algeria and Russia. Produced from radioactive decay hellium is released into the atmosphere which disperses into space.

 

Helium is the second lightest element and has the lowest melting and boiling point of any element meaning that it is a gas except under very extreme conditions. Helium is the second least reactive noble gas after neon and is non-flammable.It is also the second most abundant element and one of the first elements created after the Big Bang along with Hydrogen.

Uses

superconducting magnet.pngLiquid helium is used in superconductors as a coolant. When certain metals are cooled to extremes their electric resistance drops to zero. This phenomenon of super conduction is employed in electromagnets greatly increasing performance and they have been used in a variety of applications including the Large Hadron Collider at CERN.

 

Sound travels approximately three times faster in helium than it does in air which produces the high pitched effect when inhaled.

Inhalation of helium for several minutes can cause death due to the reduction in oxygen however divers do use a mixture of helium and oxygen when diving to deep levels. This is because using normal air would create a build up of nitrogen deposits in the blood which can lead to the bends. Using pure oxygen also can be harmful when inhaled in high concentration at depth so helium, which is non toxic, is used to dilute the oxygen concentration.

 

Helium Balloons.pngDue to helium being a non-flammable gas and the second lightest gas it has now become the first choice in airships. Before large deposists were discovered in America helium was rare on earth and during the airships boom pre-1940’s hydrogen was normally used for lift with disasterous results when the hydrogen ignighted.

Airship safety has been vastly improved with the introduction of helium which can lift 1kg for every cubic meter of helium.

 

 

 

Shell Structure

Helium.gif

 

Protons = 2

 

Neutrons =2

 

Electrons=2

 

 

 

 

 

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Absorption Lines

Helium Absorption Lines

 

Emission Lines

Helium Emission Lines