Helium
Introduction
Helium (Helium) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.
Discovery
Helium was first detected as an unknown, yellow spectral line signature in sunlight during a solar eclipse in 1868 by French astronomer, Jules Janssen (Jules Janssen). Janssen is jointly credited with detecting the element along with Norman Lockyer (Norman Lockyer) during the solar eclipse of 1868, and both men named it after the Greek word for the Sun - helios.
Physical Properties
Helium is the second lightest element and is the second most abundant element in the observable universe, being present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this figure in the Sun and in Jupiter. This is due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay.
Uses
Helium is used for many purposes that require some of its unique properties, such as its low density, low boiling point, low diffusion rate, small molecular size, high thermal conductivity, or inertness. Of the 2014 world helium total production of about 32 million kg (180 million standard cubic meters), gas extraction was 23 million kg, 78%; natural gas processing was 9 million kg, 28%, mostly from the Hugoton in Kansas, Oklahoma, and Texas. Other large reserves are in the Hugoton Gas Field, Kansas and Cliffside Gas Field in Amarillo, Texas, U.S., which have natural gas streams containing up to 2% helium volume.
See Also
