This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. Most helium in the universe is helium-4, the vast majority of which was formed during the Big Bang. Large amounts of new helium are being created by nuclear fusion of hydrogen in stars. Helium is named for the Greek Titan of the Sun, Helios. It was first detected as an unknown yellow spectral line signature in sunlight during a solar eclipse in by Georges Rayet ,  Captain C.
Haig,  Norman R. Janssen recorded the helium spectral line during the solar eclipse of while Lockyer observed it from Britain. Lockyer was the first to propose that the line was due to a new element, which he named. The formal discovery of the element was made in by two Swedish chemists, Per Teodor Cleve and Nils Abraham Langlet , who found helium emanating from the uranium ore cleveite.
In , large reserves of helium were found in natural gas fields in parts of the United States, which is by far the largest supplier of the gas today. Liquid helium is used in cryogenics its largest single use, absorbing about a quarter of production , particularly in the cooling of superconducting magnets , with the main commercial application being in MRI scanners.
Helium's other industrial uses—as a pressurizing and purge gas, as a protective atmosphere for arc welding and in processes such as growing crystals to make silicon wafers —account for half of the gas produced. A well-known but minor use is as a lifting gas in balloons and airships.
On Earth it is relatively rare—5. Most terrestrial helium present today is created by the natural radioactive decay of heavy radioactive elements thorium and uranium , although there are other examples , as the alpha particles emitted by such decays consist of helium-4 nuclei. Previously, terrestrial helium—a non-renewable resource, because once released into the atmosphere it readily escapes into space —was thought to be in increasingly short supply.
The first evidence of helium was observed on August 18, , as a bright yellow line with a wavelength of The line was detected by French astronomer Jules Janssen during a total solar eclipse in Guntur , India.
On October 20 of the same year, English astronomer Norman Lockyer observed a yellow line in the solar spectrum, which he named the D 3 because it was near the known D 1 and D 2 Fraunhofer line lines of sodium.
In , Italian physicist Luigi Palmieri detected helium on Earth for the first time through its D 3 spectral line, when he analyzed a material that had been sublimated during a recent eruption of Mount Vesuvius. Ramsay was looking for argon but, after separating nitrogen and oxygen from the gas liberated by sulfuric acid , he noticed a bright yellow line that matched the D 3 line observed in the spectrum of the Sun.
Hillebrand, however, attributed the lines to nitrogen. In , Ernest Rutherford and Thomas Royds demonstrated that alpha particles are helium nuclei by allowing the particles to penetrate the thin glass wall of an evacuated tube, then creating a discharge in the tube to study the spectrum of the new gas inside.
In , Niels Bohr published his "trilogy"   on atomic structure that included a reconsideration of the Pickering—Fowler series as central evidence in support of his model of the atom.
In , Russian physicist Pyotr Leonidovich Kapitsa discovered that helium-4 has almost no viscosity at temperatures near absolute zero , a phenomenon now called superfluidity. In , the same phenomenon was observed in helium-3 , but at temperatures much closer to absolute zero, by American physicists Douglas D. Osheroff , David M. Lee , and Robert C. The phenomenon in helium-3 is thought to be related to pairing of helium-3 fermions to make bosons , in analogy to Cooper pairs of electrons producing superconductivity.
This enabled the United States to become the world's leading supplier of helium. The goal was to supply barrage balloons with the non-flammable, lighter-than-air gas. Although the extraction process, using low-temperature gas liquefaction , was not developed in time to be significant during World War I, production continued. Helium was primarily used as a lifting gas in lighter-than-air craft. During World War II, the demand increased for helium for lifting gas and for shielded arc welding.
The helium mass spectrometer was also vital in the atomic bomb Manhattan Project. The government of the United States set up the National Helium Reserve in at Amarillo, Texas , with the goal of supplying military airships in time of war and commercial airships in peacetime. Helium use in the United States in was more than eight times the peak wartime consumption. Bureau of Mines arranged for five private plants to recover helium from natural gas. This helium-nitrogen mixture was injected and stored in the Cliffside gas field until needed, at which time it was further purified.
Helium produced between and was about In , a small amount of By , commercial quantities of Grade A In the mids, a new plant in Arzew , Algeria, producing 17 million cubic meters million cubic feet began operation, with enough production to cover all of Europe's demand.
Meanwhile, by , the consumption of helium within the U. Algeria quickly became the second leading producer of helium. As of , the United States National Helium Reserve accounted for 30 percent of the world's helium. Other large reserves were in the Hugoton in Kansas , United States, and nearby gas fields of Kansas and the panhandles of Texas and Oklahoma. New helium plants were scheduled to open in in Qatar , Russia, and the US state of Wyoming , but they were not expected to ease the shortage.
In , Qatar started up the world's largest helium unit,  although the Qatar diplomatic crisis severely affected helium production there. In the perspective of quantum mechanics , helium is the second simplest atom to model, following the hydrogen atom.
Helium is composed of two electrons in atomic orbitals surrounding a nucleus containing two protons and usually two neutrons. As in Newtonian mechanics, no system that consists of more than two particles can be solved with an exact analytical mathematical approach see 3-body problem and helium is no exception. Thus, numerical mathematical methods are required, even to solve the system of one nucleus and two electrons. The nucleus of the helium-4 atom is identical with an alpha particle.
High-energy electron-scattering experiments show its charge to decrease exponentially from a maximum at a central point, exactly as does the charge density of helium's own electron cloud. This symmetry reflects similar underlying physics: Adding another of any of these particles would require angular momentum and would release substantially less energy in fact, no nucleus with five nucleons is stable.
This arrangement is thus energetically extremely stable for all these particles, and this stability accounts for many crucial facts regarding helium in nature. For example, the stability and low energy of the electron cloud state in helium accounts for the element's chemical inertness, and also the lack of interaction of helium atoms with each other, producing the lowest melting and boiling points of all the elements. In a similar way, the particular energetic stability of the helium-4 nucleus, produced by similar effects, accounts for the ease of helium-4 production in atomic reactions that involve either heavy-particle emission or fusion.
Some stable helium-3 2 protons and 1 neutron is produced in fusion reactions from hydrogen, but it is a very small fraction compared to the highly favorable helium The unusual stability of the helium-4 nucleus is also important cosmologically: So tight was helium-4 binding that helium-4 production consumed nearly all of the free neutrons in a few minutes, before they could beta-decay, and also leaving few to form heavier atoms such as lithium, beryllium, or boron.
Helium-4 nuclear binding per nucleon is stronger than in any of these elements see nucleogenesis and binding energy and thus, once helium had been formed, no energetic drive was available to make elements 3, 4 and 5.
It was barely energetically favorable for helium to fuse into the next element with a lower energy per nucleon , carbon. However, due to lack of intermediate elements, this process requires three helium nuclei striking each other nearly simultaneously see triple alpha process. There was thus no time for significant carbon to be formed in the few minutes after the Big Bang, before the early expanding universe cooled to the temperature and pressure point where helium fusion to carbon was no longer possible.
All heavier elements including those necessary for rocky planets like the Earth, and for carbon-based or other life have thus been created since the Big Bang in stars which were hot enough to fuse helium itself.
Helium is the second least reactive noble gas after neon , and thus the second least reactive of all elements. Because of helium's relatively low molar atomic mass, its thermal conductivity , specific heat , and sound speed in the gas phase are all greater than any other gas except hydrogen. Helium is the least water- soluble monatomic gas,  and one of the least water-soluble of any gas CF 4 , SF 6 , and C 4 F 8 have lower mole fraction solubilities: Most extraterrestrial helium is found in a plasma state, with properties quite different from those of atomic helium.
In a plasma, helium's electrons are not bound to its nucleus, resulting in very high electrical conductivity, even when the gas is only partially ionized. The charged particles are highly influenced by magnetic and electric fields.
For example, in the solar wind together with ionized hydrogen, the particles interact with the Earth's magnetosphere , giving rise to Birkeland currents and the aurora. Unlike any other element, helium will remain liquid down to absolute zero at normal pressures. This is a direct effect of quantum mechanics: Solid helium requires a temperature of 1—1. At room temperature, this requires about , atm.
Below its boiling point of 4. Below the lambda point, however, helium does not boil, and it expands as the temperature is lowered further. This may be an effect of its boiling point being so close to absolute zero, preventing random molecular motion thermal energy from masking the atomic properties. Due to its high thermal conductivity , when it boils, it does not bubble but rather evaporates directly from its surface.
Helium-3 also has a superfluid phase, but only at much lower temperatures; as a result, less is known about the properties of the isotope. Current theory explains this using the two-fluid model for helium II. In this model, liquid helium below the lambda point is viewed as containing a proportion of helium atoms in a ground state , which are superfluid and flow with exactly zero viscosity, and a proportion of helium atoms in an excited state, which behave more like an ordinary fluid.
If the interior of the container is heated, the superfluid helium changes to non-superfluid helium. In order to maintain the equilibrium fraction of superfluid helium, superfluid helium leaks through and increases the pressure, causing liquid to fountain out of the container.
Most materials that conduct heat well have a valence band of free electrons which serve to transfer the heat. The flow of heat is governed by equations that are similar to the wave equation used to characterize sound propagation in air. When heat is introduced, it moves at 20 meters per second at 1. This film is called a Rollin film and is named after the man who first characterized this trait, Bernard V. Waves propagating across a Rollin film are governed by the same equation as gravity waves in shallow water, but rather than gravity, the restoring force is the van der Waals force.
There are nine known isotopes of helium, but only helium-3 and helium-4 are stable. In the Earth's atmosphere, one atom is 3 He for every million that are 4 He. The most common isotope, helium-4, is produced on Earth by alpha decay of heavier radioactive elements; the alpha particles that emerge are fully ionized helium-4 nuclei. Helium-4 is an unusually stable nucleus because its nucleons are arranged into complete shells. It was also formed in enormous quantities during Big Bang nucleosynthesis.
Helium-3 is present on Earth only in trace amounts. Most of it has been present since Earth's formation, though some falls to Earth trapped in cosmic dust. Thus in the interstellar medium , the proportion of 3 He to 4 He is about times higher than on Earth. The Moon 's surface contains helium-3 at concentrations on the order of 10 ppb , much higher than the approximately 5 ppt found in the Earth's atmosphere.
Liquid helium-4 can be cooled to about 1 kelvin using evaporative cooling in a 1-K pot. It is possible to produce exotic helium isotopes , which rapidly decay into other substances. And you suddenly have visions of ornamental wall Setbacks seem to target those least deserving.
But recovery comes down to attitude Is it really an epidemic? Is Autism an epidemic? I decided to make a cup of tea and think about it. On my way, I stepped over an artistically-brilliant sketch of a kitten in Drowning Health-bringing, wonderful, cleansing, complete, maker of icicles, snowflakes unique, Lifeline of coral, home of the fish, thirst-quenching The last competition I entered didn't go nearly as well but i am still happy to be collecting the coins on all my articles each day.
I have also started a website at http: Eventually I hope it will become a good resource for anyone wanting to work at home and earn money without being stuck trawling through the fake opportunities out there. Here are some more of my articles if anyone is interested. Love I can see you over the ocean And hear your voice in the air But your touch is only in my memories of our interlude And your skin is too distant Why you should keep a journal of your travels I'm sitting here with a photo album in my lap.
It's my aunt's memories of Canada in the early 70s. The pages are full of smiling strange faces. Those things you pack "just in case" should be left at home. Can it be any more blunt than that? Packing for a trip Winter Is there an unwritten mantra, that declares we must find the beauty in winter? Winter and its crystalline landscape. Icicles hanging from delica Forgiveness My son's a handsome kid.
He looks just like his father did when he was But Elijah isn't at all like his father in personality. My son is the re It has rated as consistently awful! But I kinda like it. I do know what I did wrong in this piece, but since it was my sounding board for understanding the system, I'm not sure I will bother leapfrogging it.
Emma wasn't even supposed to be in the wedding party. I'd chosen my sister as bridesmaid as soon as Jeff proposed, but by the time the big day rolled around she was only weeks away from giving birth, so Emma graciously stepped into the role.
Welcome from Eliza I'm hoping this will become a good place to chat about why we love Helium: It would also be great to link any non-Helium piece of creative writing that you think is fantastic.
Feel free to paste articles if you wish, but make it inside an LJ CUT if it's more than about ten lines. Melting point The temperature at which the solid—liquid phase change occurs. Boiling point The temperature at which the liquid—gas phase change occurs. Sublimation The transition of a substance directly from the solid to the gas phase without passing through a liquid phase.
Relative atomic mass The mass of an atom relative to that of carbon This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists, the value given is the abundance weighted average.
Isotopes Atoms of the same element with different numbers of neutrons. CAS number The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems. Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.
Where the element is most commonly found in nature, and how it is sourced commercially. Atomic radius, non-bonded Half of the distance between two unbonded atoms of the same element when the electrostatic forces are balanced.
These values were determined using several different methods. Covalent radius Half of the distance between two atoms within a single covalent bond. Values are given for typical oxidation number and coordination. Electron affinity The energy released when an electron is added to the neutral atom and a negative ion is formed. Electronegativity Pauling scale The tendency of an atom to attract electrons towards itself, expressed on a relative scale.
First ionisation energy The minimum energy required to remove an electron from a neutral atom in its ground state. The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0. The sum of the oxidation states within a compound or ion must equal the overall charge.
Data for this section been provided by the British Geological Survey. An integrated supply risk index from 1 very low risk to 10 very high risk. This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores. The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply. The availability of suitable substitutes for a given commodity. The percentage of an element produced in the top producing country.
The higher the value, the larger risk there is to supply. The percentage of the world reserves located in the country with the largest reserves. A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.
Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K. A measure of the stiffness of a substance. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.
A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain. A measure of how difficult it is to compress a substance.
It is given by the ratio of the pressure on a body to the fractional decrease in volume. A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site.
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Nor shall the RSC be in any event liable for any damage to your computer equipment or software which may occur on account of your access to or use of the Site, or your downloading of materials, data, text, software, or images from the Site, whether caused by a virus, bug or otherwise. Jump to main content. Glossary Allotropes Some elements exist in several different structural forms, called allotropes. Glossary Group A vertical column in the periodic table.
Glossary Image explanation Murray Robertson is the artist behind the images which make up Visual Elements. Appearance The description of the element in its natural form. Biological role The role of the element in humans, animals and plants. Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially. Helium was detected in the sun by its spectral lines many years before it was found on Earth.
A colourless, odourless gas that is totally unreactive.
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Helium is an online writing community enabling writers to submit articles, capture publisher writing assignments bounties, and get territorios-luchas.tkd: This Helium review has been published to educate freelance writers and researchers about job opportunities. Helium offers freelance writing jobs to potential candidates. You can work as a writer or a copy writer. Helium pays through Paypal.
Joined Helium almost a year ago, wrote bits on and off, actually had a payment from them a couple of months ago but interest slowly waned for a while. Seem to be writing at least one article a day now though, and waiting for earnings to pick up again. Originally, writers could post to Helium under their by-line, and articles remained their property. Helium shared ad revenue and helped to sell publishing rights to customers seeking content writing services. From time to time a writer might receive a $5 bonus when someone published the .