What is Helium?

Helium in the periodic table

Helium is a noble gas or group-18 element in the periodic table with the symbol He and atomic number 2. It is the only noble gas in the periodic table that was discovered by an astronomer. Helium is the first member of the noble gas family with electron configuration 1s2.

It was named by scientists Lockyer and Frankland. The name of the noble gas helium is derived from the Greek word “Helios” meaning Sun. Scientists detected a huge amount of helium in the Sun before it was discovered.

Properties

• Relative atomic mass: 4.003
• State at 20°C: Colourless gas
• Melting point: Unknown
• Boiling point: −268.928 °C, −452.07 °F, 4.222 K
• Density (g/cm3): 0.000164
• CAS number: 7440–59–7
• Chem Spider ID: 22423

Facts about helium

• It is a colorless, borderless, totally unreactive gas in our universe.
• It is a non-toxic gas that has no biological functions.
• It is the second most abundant element in our universe after hydrogen.
• It is formed in stars and formed on earth by alpha particle radiation from radioactive elements. Nuclear fusion of hydrogen generates a significant amount of He gas in stars.
• The major source of helium is natural gas which contains up to 7% of He gas.
• Due to the filled subshell, it is inert for chemical reactions.
• There are nine known isotopes of helium but only He-3 and He-4 are stable.

Uses of Helium gas

• Primarily helium is used for various research and meteorological balloons.
• It holds the lowest melting points among all other elements. Therefore, it is used as a cooling medium for superconducting magnets in MRI scanners and NMR spectrometers.
• It is also used for cooling satellite instruments and space vehicles.
• It is also used for making germanium crystals and silicon crystals.
• It is used to create an inert protective atmosphere for making fiber optics and semiconductors, and for arc welding.
• It is also used to detect leaks in car air-conditioning systems.
• A mixture of helium and oxygen is used to create an artificial atmosphere for deep-sea divers.
• Helium-ion microscope provides better image resolution than a scanning electron microscope.
• Due to its low melting point, liquid helium has been used in cryogenics, magnetic resonance imaging (MRI), and superconducting magnets.

References

• Helium Element information, properties, and uses | rsc.org
• Helium Element, Facts, Properties — Priyamstudycentre.com
• Helium — Wikipedia
• Helium Definition, Properties, Uses, & Facts | Britannica