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Discovery date            1895

Discovered by Sir William Ramsay in London, and independently by Per Teodor Cleve and Nils Abraham Langlet in Uppsala, Sweden.

The name is derived from the Greek, 'helios' meaning sun, as it was in the sun's corona that helium was first detected. Helium was detected in the sun by its spectral lines many years before it was found on Earth.

Allotropes     

Group  18                                            Melting point  Unknown

Period  1                                              Boiling point    −268.928°C, −452.07°F, 4.222 K

Block   s                                               Density (g cm−3)         0.000164

Atomic number           2                                  Relative atomic mass 4.003 

State at 20°C   Gas                              Key isotopes    4He

Electron configuration            1s2                   CAS number    7440-59-7

"Helium, deriving its name from the Greek word 'helios' meaning sun, was first detected in the sun's corona through its spectral lines long before its discovery on Earth. Learn about the fascinating history of helium's detection in the sun and its subsequent identification on our planet."

Helium, an unreactive and colorless gas, is not only the second most abundant element in the universe but also plays a significant role in various applications.

Its cooling properties are utilized in cutting-edge technologies like the Large Hadron Collider (LHC), MRI scanners, and NMR spectrometers. Additionally, helium keeps satellite instruments cool and has been instrumental in powering Apollo space vehicles by cooling liquid oxygen and hydrogen.

Its low density makes it a popular choice for filling decorative balloons, weather balloons, and airships, serving both entertainment and scientific purposes. Unlike hydrogen, which was previously used for the same purpose, helium's non-reactivity ensures safer applications.

Common oxidation states   

Isotope Atomic mass   Natural abundance (%)          

 3He                 3.016                           0.000134                                            

4He                  4.003                           99.9999

Due to its inert nature, helium is employed as a protective atmosphere in the production of fiber optics, semiconductors, and arc welding. It also finds use in detecting leaks, inflating car airbags quickly after impact, and creating an artificial atmosphere for deep-sea divers working under pressurized conditions.

The remarkable applications extend to technology, where helium-neon gas lasers are used for barcode scanning at supermarket checkouts, while the new helium-ion microscope provides superior image resolution compared to scanning electron microscopes.

Despite its significance, helium is an endangered element with challenges in its extraction and limited natural reserves. The majority of helium is sourced from natural gas, and recycling infrastructure is crucial to conserve this precious resource. Proper recycling measures, exploring alternatives, and implementing price controls can aid in saving helium and ensuring a stable supply for various scientific and industrial needs.

Uncover the remarkable journey of helium, from its discovery in the sun's corona to its essential role in modern applications, and the urgent need to protect this invaluable element for future generations.