20th October 1868. The Eccentricity of Helium.
Helium gas (He) is the lightest of the Noble Elements, having an isotope constituting the 2nd most abundant element by mass in the universe, after Hydrogen, but is exceptionally rare on Earth.(1)
Hell would freeze over before Helium solidifies and as its boiling point is the lowest of all elements it has a wide variety of uses, especially where metals need cooling as in MRI scanners.
Today in 1868 the British astronomer [Sir]Norman Lockyer FRS (1836-1920) pointed his 6 inch telescope (not directly!) at an eclipsed sun, examining the reduced light with a spectroscope.
He noticed a faint yellow line in the corona spectrum thus confirming a previous observation. (2)
Lockyer assumed the ‘spectrum line’ could only come from the sun and with the help of chemist Edward Frankland, deduced that it represented a new element. Not believed for a time Helium was confirmed in 1895 in terrestrial rocks after Sir William Ramsay treated the mineral Cleveite with acids.
Lockyer assumed Helium was a metal and gave it the ‘ium ‘ ending to the Greek ‘Helios’, the Greek sun-god.
Helium is getting scarce on earth with most of it stored in America and only new finds trapped in Natural Gas will ensure its supply in the future. So go easy on those balloons!
(1) Noble Gases are Monatomic, gases where atoms are not bound together. The first person who set apart and characterised the Noble Gases was Henry Cavendish in 1875.
He distinguished these elements by chemically removing all the oxygen and nitrogen from a receptacle of air.
Helium-4 is by far the most natural occurring isotope (variation) of the gas, is unusual as a Noble Gas having only 2 electrons (normally 8), in its Valence (outer) shell. (See Diagram).
Having two protons (red) and two neutrons (purple) its mass is 4. (See Diagram above).
(2) Observation August 18th in India.
The Inert major atmospheric gas, Nitrogen (N) is not a Noble Gas ( which are only found in Group O (8) in The Periodic Table).
Ref:Nature’s Building Blocks: A-Z Guide to Elements. John Emsley. OUP 2001.
bbc.co.uk/science 28.6.2016 Helen Briggs. Helium discoveries in Tanzania a game changer/Pic of balloons.
wikipedia.org/helium/Pic of nucleus.
independent.co.uk/news/why world is running out of Helium. Steve Connor. 23.8.2010.
newscientist.com. Marcus Chown. 8.4.1995.