Spectral lines of helium
|ନାମ, ପ୍ରତୀକ||helium, He|
|Appearance||colorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field|
|Helium in the periodic table|
|ପରମାଣୁ କ୍ରମାଙ୍କ (Z)||2|
|ଶ୍ରେଣୀ, ବ୍ଳକ||group 18 (noble gases), s-block|
|ମୌଳିକ ପ୍ରକାର||noble gas|
|ମାନକ ପରମାଣବିକ ଓଜନ (±) (Ar)||4.002602(2)|
|ଗଳନାଙ୍କ||(at 2.5 MPa) 0.95 K (−272.20 °C, −457.96 °F)|
|ସ୍ଫୁଟନାଙ୍କ||4.22 K (−268.93 °C, −452.07 °F)|
|ଘନତା at stp (0 °C and 101.325 kPa)||0.1786 g/L|
|when liquid, at m.p.||0.145 g/cm3|
|when liquid, at b.p.||0.125 g/cm3|
|Critical point||5.19 K, 0.227 MPa|
|Heat of fusion||0.0138 kJ/mol|
|Heat of||0.0829 kJ/mol|
|Molar heat capacity||5R/2 = 20.786 J/(mol·K)|
| pressure (defined by ITS-90)|
|Electronegativity||Pauling scale: no data|
|Covalent radius||28 pm|
|Van der Waals radius||140 pm|
|Crystal structure||hexagonal close-packed (hcp)|
|Speed of sound||972 m/s|
|Thermal conductivity||0.1513 W/(m·K)|
|ଆବିଷ୍କାର||Pierre Janssen, Norman Lockyer (1868)|
|First isolation||William Ramsay, Per Teodor Cleve, Abraham Langlet (1895)|
|Most stable isotopes of helium|
== ଇତିହାସ ==Evidence of helium was first detected on August 18, 1868 as a bright yellow line with a wavelength of 587.49 nanometres in the spectrum of the chromosphere of the Sun, by French astronomer Pierre Janssen during a total solar eclipse in Guntur, India. This line was initially assumed to be sodium. On October 20 of the same year, English astronomer Norman Lockyer observed a yellow line in the solar spectrum, which he named the D3 line, for it was near the known D1 and D2 lines of sodium, and concluded that it was caused by an element in the Sun unknown on Earth. He and English chemist Edward Frankland named the element with the Greek word for the Sun. On 26 March 1895 British chemist William Ramsay isolated helium on Earth by treating the mineral cleveite with mineral acids. Ramsay was looking for argon but, after separating nitrogen and oxygen from the gas liberated by sulfuric acid, noticed a bright-yellow line that matched the D3 line observed in the spectrum of the Sun. These samples were identified as helium by Lockyer and British physicist William Crookes. It was independently isolated from cleveite the same year by chemists Per Teodor Cleve and Abraham Langlet in Uppsala, Sweden, who collected enough of the gas to accurately determine its atomic weight. Helium was also isolated by the American geochemist William Francis Hillebrand prior to Ramsay's discovery when he noticed unusual spectral lines while testing a sample of the mineral uraninite. Hillebrand, however, attributed the lines to nitrogen. His letter of congratulations to Ramsay offers an interesting case of discovery and near-discovery in science. In 1907, Ernest Rutherford and Thomas Royds demonstrated that an alpha particle is a helium nucleus. In 1908, helium was first liquefied by Dutch physicist Heike Kamerlingh Onnes by cooling the gas to less than one kelvin. He tried to solidify it by further reducing the temperature but failed because helium does not have a triple point temperature where the solid, liquid, and gas phases are at equilibrium. It was first solidified in 1926 by his student Willem Hendrik Keesom by subjecting helium to 25 atmospheres of pressure. In 1938, Russian physicist Pyotr Leonidovich Kapitsa discovered that helium-4 has almost no viscosity at temperatures near absolute zero, a phenomenon now called superfluidity. In 1972, the same phenomenon was observed in helium-3 by American physicists Douglas D. Osheroff, David M. Lee, and Robert C. Richardson.
Notes === ବୈଜ୍ଞାନିକ ଆବିଷ୍କାର ===Discovery Information Who: Sir William Ramsey, Nils Langet, P T Cleve When: 1895 Where: Scotland/Sweden
Name Origin Greek: helios (sun). ===ଉତ୍ପାଦନ===Sources Found in natural gas deposits and in the air (5 parts per billion) Constantly lost to space; replenished by radioactive decay (alpha particles). Helium is the second most abundant element in the universe by mass (25%). Most of the helium supplied around the world comes from the area around Amarillo, Texas. Annual commercial production is around 4500 tons.
Universe: 2.3 x 105 ppm (by weight) Sun: 2.3 x 105 ppm (by weight) Atmosphere: 5.2 ppm Earth's Crust: 0.008 ppm Seawater: 7 x 10-6 ppm
ହିଲିୟମ ପରମାଣୁସମ୍ପାଦନ କରନ୍ତୁ
note:Helium has the lowest melting and boiling point of any element. Liquid Helium is called a "quantum fluid" as it displays atomic properties on a macroscopic scale. The viscosity of liquid helium is 25 micropoises (water has a viscosity of 10,000 micropoises). As helium is cooled below its transition point, it has an unusual property of superfluidity with a viscosity approaching zero micropoises. In addition, liquid helium has extremely high thermal conductivity. Helium is the second most abundant and second lightest element in the periodic table. It is also the least reactive of all the group 18 (noble gases) elements. One cubic metre of helium will lift 1kg. Helium is the preferred choice for airships as although it is more expensive it is not flammable and has 92% the lifting power of hydrogen. The voice of a person who has inhaled helium temporarily sounds high-pitched, resembling those of the cartoon characters "Alvin and the Chipmunks". This is because the speed of sound in helium is nearly three times that in air. Although the vocal effect of inhaling helium may be amusing, it can be dangerous if done to excess since helium is a simple asphyxiant, thus it displaces oxygen needed for normal respiration. Death by asphyxiation will result within minutes if pure helium is breathed continuously.
ତରଳ ଓ ଗ୍ୟାସୀୟ ଅବସ୍ଥାସମ୍ପାଦନ କରନ୍ତୁ
କଠିନ ଓ ପ୍ଲାଜ୍ମା ଅବସ୍ଥାସମ୍ପାଦନ କରନ୍ତୁ
== ସମସ୍ଥାନିକ ==3He [1 neutrons] Abundance: 0.000137% Stable with 1 neutron Extraplanetary material, such as lunar and asteroid regolith, have trace amounts of helium-3 from being bombarded by solar winds. The Moon's surface contains helium-3 at concentrations on the order of 0.01 ppm.[
4He [2 neutrons] Abundance: 99.999863% Stable with 2 neutrons Liquid helium-4 can be cooled to about 1 kelvin using evaporative cooling.
5He [3 neutrons] Abundance: Half life: 7.00(30) x 10-24 seconds Decays to 4He. Highly unstable, decays to 4He.
6He [4 neutrons] Abundance: Half life: 806.7(15) ms [ beta- ] Decays to 6Li. Produced from 7He or 11Li.
7He [5 neutrons] Abundance: Half life: 2.9(5)-21 seconds Highly unstable, decays to 6He.
8He [6 neutrons] Abundance: Half life: 119.0(15) ms Produced from 9He, decomposes to 7Li through beta decay then emits a delayed neutron.
9He [7 neutrons] Abundance: Half life: 7(4) x 10-21 seconds Highly unstable, decays to 8He.
10He [8 neutrons] Abundance: Half life: 2.7(18) x 10-21 seconds Highly unstable, decays to 9He.
==ବ୍ୟବହାର==Used in balloons as it is lighter than air, and unlike hydrogen, not flammable; deep sea diving and welding. Also used in very low temperature research and nuclear power plant coolant. Future possible uses include use as coolant for nuclear fusion power plants and in superconducting electric systems. At extremely low temperatures, liquid helium is used to cool certain metals to produce superconductivity, such as in superconducting magnets used in magnetic resonance imaging. Helium at low temperatures is also used in cryogenics. Because it is inert, helium is used as a protective gas in growing silicon and germanium crystals, in titanium and zirconium production, in gas chromatography, and as an atmosphere for protecting historical documents. This property also makes it useful in supersonic wind tunnels
- Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.
- Bureau of Mines (1967). Minerals yearbook mineral fuels Year 1965, Volume II (1967). U. S. Government Printing Office.
- Committee on the Impact of Selling the Federal Helium Reserve, Commission on Physical Sciences, Mathematics, and Applications, Commission on Engineering and Technical Systems, National Research Council (2000). The Impact of Selling the Federal Helium Reserve. The National Academies Press. ISBN 0-309-07038-4. Retrieved April 2, 2010.CS1 maint: Multiple names: authors list (link)
- Emsley, John (1998). The Elements (3rd ed.). New York: Oxford University Press. ISBN 978-0-19-855818-7.
- "Mineral Information for Helium" (PDF). United States Geological Survey (usgs.gov). Retrieved 2007-01-05.
- Vercheval, J. (2003). "The thermosphere: a part of the heterosphere". Belgian Institute for Space Aeronomy. Archived from the original on 2005-01-01. Retrieved 2008-07-12.
- Zastenker, G. N.; et al. (2002). "Isotopic Composition and Abundance of Interstellar Neutral Helium Based on Direct Measurements". Astrophysics. 45 (2): 131–142. Bibcode:2002Ap.....45..131Z. doi:10.1023/A:1016057812964.CS1 maint: Explicit use of et al. (link)
ବାହାର ଆଧାରସମ୍ପାଦନ କରନ୍ତୁ
- U.S. Government's Bureau of Land Management: Sources, Refinement, and Shortage. With some history of helium.
- U.S. Geological Survey publications on helium beginning 1996: Helium
- Where is all the helium? Aga website
- It's Elemental – Helium
- Chemistry in its element podcast (MP3) from the Royal Society of Chemistry's Chemistry World: Helium
- More detail
- Helium at The Periodic Table of Videos (University of Nottingham)
- Helium at the Helsinki University of Technology; includes pressure-temperature phase diagrams for helium-3 and helium-4
- Lancaster University, Ultra Low Temperature Physics – includes a summary of some low temperature techniques
- Physics in Speech with audio samples that demonstrate the unchanged voice pitch
- Article about helium and other noble gases
- Helium shortage
- Kramer, David (May 22, 2012). "Senate bill would preserve US helium reserve: Measure would give scientists first dibs on helium should a shortage develop. Physics Today web site".