• Helium is a colorless odorless monatomic noble gas element
• Helium discovered by Pierre Janssen, Norman Lockyer (1868)
• Helium first isolation by William Ramsay, Per Teodor Cleve, Abraham Langlet (1895)
• Helium Named after Helios, Greek Titan of the Sun
• Helium has a valence of zero and is chemically unreactive under all normal conditions
• Helium is the second lightest and second most abundant element in the universe after hydrogen
• Majority of helium was formed during the Big Bang. Large amounts of new helium are being created by nuclear fusion of hydrogen in stars
• Elements other than hydrogen and helium today account for only 2% of the mass of atomic matter in the universe, Helium making up about 23%
• Helium is the only element to remain liquid down to absolute zero at normal pressures and requires much higher pressures to become solid
• Helium liquid can be cooled to point where it becomes a superfluid showing no measurable viscosity and thermal conductivity greater than that of any other known substance
• Helium has nine known isotopes only helium-3 and helium-4 are stable
• Helium present today is created by the natural radioactive decay of heavy radioactive elements producing alpha particles (helium-4 nuclei)
• Helium is trapped with natural gas in concentrations as great as 7% by volume, from which it is extracted commercially by fractional distillation
• Helium once released into the atmosphere eventually escapes into space
• Helium has many uses that require some of its unique properties, like low boiling point, low density, low solubility, high thermal conductivity, or inertness
• Liquid helium is used in cryogenics, particularly in the cooling of superconducting magnets, with the main commercial application being in MRI scanners
• Helium is used as a protective atmosphere for arc welding and in processes such as growing crystals to make silicon wafers
• Helium is used in balloons and airships as it is safer than hydrogen
• Helium is used as a plasma gas in thermal spray processes
• Helium diffuses through solids three times faster than air, it is used as a tracer gas to detect leaks in high-vacuum equipment
• The age of rocks and minerals that contain uranium and thorium can be estimated by measuring the level of helium with a process known as helium dating
• Helium gas mixtures are used for breathing during deep diving to reduce the effects of narcosis
• Helium is not toxic, but is an asphyxiant

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