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Atomic Number: 36

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In Britain 1898 Sir William Ramsay (A Scottish Chemist) and Morris Travers (A English Chemist) were doing an experiment and found residue leftover from evaporating most of the components in liquid air.

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In Britain 1898 Sir William Ramsay (A Scottish Chemist) and Morris Travers (A English Chemist) were doing an experiment and found residue leftover from evaporating most of the components in liquid air.

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This leftover residue that they discovered was Krypton.

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*The Earths Atmosphere is about 0.0001% Krypton

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*The Earths Atmosphere is about 0.0001% Krypton

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*Named after a Greek word Kryptos meaning "Hidden"

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*Named after a Greek word Kryptos meaning "Hidden"

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Description: Colorless, Tasteless, and Odorless Gas (heavy)

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Description: Colorless, Tasteless, and Odorless Gas (heavy)

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* For filling gas for energy-saving-lights

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* For filling gas for energy-saving-lights

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*Product of nuclear reactors in the Cold War

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*Product of nuclear reactors in the Cold War

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Krypton like most elements that are gas are usually unseen and unheard of. This element doesn't really seem that important and yes it has very limited uses but it has many possibilities and since this gas is so undetectable you may think you never use it. The truth is we do all the time (manly in extreme cold or heat). It is used as a great insulator in paint and is used in energy saving lights. It keeps the electric bill down and you nice and cold or hot (depending on what you use it to insolate) and because its so heavy it has many other uses in the future.

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Krypton - Element information, properties and uses | Periodic Table

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Element Krypton (Kr), Group 18, Atomic Number 36, p-block, Mass 83.798. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images.

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A krypton-filled discharge tube glowing white

Krypton

Pronunciation

​(KRIP-ton)

Appearance

colorless gas, exhibiting a whitish glow in an electric field

Standard atomic weight A r, std(Kr)

83.798(2) [1]

Krypton in the periodic table

(Atomic number Z)

36

Group

group 18 (noble gases)

Period

period 4

Block

p-block

Element category

Noble gas

Electron configuration

[ Ar] 3d ¹⁰ 4s ² 4p ⁶

Electrons per shell

2, 8, 18, 8

Physical properties

at Phase STP
gas

Melting point

115.78 K ​(−157.37 °C, ​−251.27 °F)

Boiling point

119.93 K ​(−153.415 °C, ​−244.147 °F)

Density (at STP)

3.749 g/L

when liquid (at b.p.)

2.413 g/cm ³[2]

Triple point

115.775 K, ​73.53 kPa[3][4]

Critical point

209.48 K, 5.525 MPa[4]

Heat of fusion

1.64 kJ/mol

Heat of vaporization

9.08 kJ/mol

Molar heat capacity

20.95[5] J/(mol·K)

Vapor pressure

P (Pa)

1

10

100

1 k

10 k

100 k

at T (K)

59

65

74

84

99

120

Atomic properties

Oxidation states

0, +1, +2 (rarely more than 0; oxide is unknown)

Electronegativity

Pauling scale: 3.00

Ionization energies

1st: 1350.8 kJ/mol

2nd: 2350.4 kJ/mol

3rd: 3565 kJ/mol

Covalent radius

116±4 pm

Van der Waals radius

202 pm

Spectral lines of krypton

Other properties

Natural occurrence
primordial

Crystal structure

​ face-centered cubic (fcc)

Speed of sound

(gas, 23 °C) 220 m·s −1
(liquid) 1120 m/s

Thermal conductivity

9.43×10 −3 W/(m·K)

Magnetic ordering

diamagnetic[6]

Magnetic susceptibility

−28.8·10 −6 cm ³/mol (298 K)[7]

CAS Number

7439-90-9

History

Discovery and first isolation

William Ramsay and Morris Travers (1898)

Main isotopes of krypton

Category: Krypton
| references

Krypton (from Ancient Greek: κρυπτός, kryptos "the hidden one") is a chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. With rare exceptions, krypton is chemically inert.

Krypton, like the other noble gases, is used in lighting and photography. Krypton light has many spectral lines, and krypton plasma is useful in bright, high-powered gas lasers (krypton ion and excimer lasers), each of which resonates and amplifies a single spectral line. Krypton fluoride also makes a useful laser medium. From 1960 to 1983, the official length of a meter was defined by the 606-nanometer wavelength of the orange spectral line of krypton-86, because of the high power and relative ease of operation of krypton discharge tubes.

Krypton was discovered in Britain in 1898 by William Ramsay, a Scottish chemist, and Morris Travers, an English chemist, in residue left from evaporating nearly all components of liquid air. Neon was discovered by a similar procedure by the same workers just a few weeks later. William Ramsay was awarded the 1904 Nobel Prize in Chemistry for discovery of a series of noble gases, including krypton.

In 1960, the International Bureau of Weights and Measures defined the meter as 1,650,763.73 wavelengths of light emitted by the krypton-86 isotope. This agreement replaced the 1889 international prototype meter, which was a metal bar located in Sèvres. This also obsoleted the 1927 definition of the ångström based on the red cadmium spectral line, replacing it with 1 Å = 10 −10 m. The krypton-86 definition lasted until the October 1983 conference, which redefined the meter as the distance that light travels in vacuum during 1/299,792,458 s.

Characteristics

Krypton is characterized by several sharp emission lines ( spectral signatures) the strongest being green and yellow. Krypton is one of the products of uranium fission. Solid krypton is white and has a face-centered cubic crystal structure, which is a common property of all noble gases (except helium, which has a hexagonal close-packed crystal structure).

Naturally occurring krypton in Earth's atmosphere is composed of five stable isotopes, plus one isotope ( ⁷⁸Kr) with such a long half-life (9.2×10 ²¹ years) that it can be considered stable. (This isotope has the second-longest known half-life among all isotopes for which decay has been observed; it undergoes double electron capture to ⁷⁸ Se). In addition, about thirty unstable isotopes and isomers are known. Traces of ⁸¹Kr, a cosmogenic nuclide produced by the cosmic ray irradiation of ⁸⁰Kr, also occur in nature: this isotope is radioactive with a half-life of 230,000 years. Krypton is highly volatile and does not stay in solution in near-surface water, but ⁸¹Kr has been used for dating old (50,000-800,000 years) groundwater.

is an inert radioactive noble gas with a half-life of 10.76 years. It is produced by the fission of uranium and plutonium, such as in nuclear bomb testing and nuclear reactors. ⁸⁵Kr is released during the reprocessing of fuel rods from nuclear reactors. Concentrations at the North Pole are 30% higher than at the South Pole due to convective mixing.

Like the other noble gases, krypton is chemically highly unreactive. The rather restricted chemistry of krypton in the +2 oxidation state parallels that of the neighboring element bromine in the +1 oxidation state; due to the scandide contraction it is difficult to oxidize the 4p elements to their group oxidation states. Until the 1960s no noble gas compounds had been synthesized.

However, following the first successful synthesis of xenon compounds in 1962, synthesis of krypton difluoride (KrF) was reported in 1963. In the same year, KrF was reported by Grosse, et al., but was subsequently shown to be a mistaken identification. Under extreme conditions, krypton reacts with fluorine to form KrF ₂ according to the following equation:

Krypton gas in a krypton fluoride laser absorbs energy from a source, causing the krypton to react with fluorine gas, producing the exciplex krypton fluoride, a temporary complex in an excited energy state:

The complex can undergo spontaneous or stimulated emission, reducing its energy state to a metastable, but highly repulsive ground state. The ground state complex quickly dissociates into unbound atoms:

The result is an exciplex laser which radiates energy at 248 nm, near the ultraviolet portion of the spectrum, corresponding with the energy difference between the ground state and the excited state of the complex.

Compounds with krypton bonded to atoms other than fluorine have also been discovered. There are also unverified reports of a barium salt of a krypton oxoacid. ArKr⁺ and Kr H⁺ polyatomic ions have been investigated and there is evidence for Kr Xe or KrXe⁺.

The reaction of KrF with B(OTeF) produces an unstable compound, Kr(OTeF), that contains a krypton- oxygen bond. A krypton- nitrogen bond is found in the cation [HC≡N-Kr-F], produced by the reaction of KrF with [HC≡NH][AsF] below −50 °C. HKrCN and HKrC≡CH (krypton hydride-cyanide and hydrokryptoacetylene) were reported to be stable up to 40 K.

Krypton hydride (Kr(H ₂) ₄) crystals can be grown at pressures above 5 GPa. They have a face-centered cubic structure where krypton octahedra are surrounded by randomly oriented hydrogen molecules.

Natural occurrence

Earth has retained all of the noble gases that were present at its formation except helium. Krypton's concentration in the atmosphere is about 1 ppm. It can be extracted from liquid air by fractional distillation. The amount of krypton in space is uncertain, because measurement is derived from meteoric activity and solar winds. The first measurements suggest an abundance of krypton in space.

Applications

Krypton's multiple emission lines make ionized krypton gas discharges appear whitish, which in turn makes krypton-based bulbs useful in photography as a white light source. Krypton is used in some photographic flashes for high speed photography. Krypton gas is also combined with mercury to make luminous signs that glow with a bright greenish-blue light.

Krypton is mixed with argon in energy efficient fluorescent lamps, reducing the power consumption, but also reducing the light output and raising the cost. Krypton costs about 100 times as much as argon. Krypton (along with xenon) is also used to fill incandescent lamps to reduce filament evaporation and allow higher operating temperatures. A brighter light results with more blue color than conventional incandescent lamps.

Krypton's white discharge is sometimes used as an artistic effect in gas discharge "neon" tubes. Krypton produces much higher light power than neon in the red spectral line region, and for this reason, red lasers for high-power laser light-shows are often krypton lasers with mirrors that select the red spectral line for laser amplification and emission, rather than the more familiar helium-neon variety, which could not achieve the same multi-watt outputs.

The krypton fluoride laser is important in nuclear fusion energy research in confinement experiments. The laser has high beam uniformity, short wavelength, and the spot size can be varied to track an imploding pellet.

In experimental particle physics, liquid krypton is used to construct quasi-homogeneous electromagnetic calorimeters. A notable example is the calorimeter of the NA48 experiment at CERN containing about 27 tonnes of liquid krypton. This usage is rare, since liquid argon is less expensive. The advantage of krypton is a smaller Molière radius of 4.7 cm, which provides excellent spatial resolution with little overlapping. The other parameters relevant for calorimetry are: radiation length of X ₀=4.7 cm, and density of 2.4 g/cm ³.

The sealed spark gap assemblies in ignition exciters in some older jet engines contain a small amount of krypton-85 to produce consistent ionization levels and uniform operation.

Krypton-83 has application in magnetic resonance imaging (MRI) for imaging airways. In particular, it enables the radiologist to distinguish between hydrophobic and hydrophilic surfaces containing an airway.

Although xenon has potential for use in computed tomography (CT) to assess regional ventilation, its anesthetic properties limit its fraction in the breathing gas to 35%. A breathing mixture of 30% xenon and 30% krypton is comparable in effectiveness for CT to a 40% xenon fraction, while avoiding the unwanted effects of a high partial pressure of xenon gas.

The metastable isotope krypton-81m is used in nuclear medicine for lung ventilation/perfusion scans, where it is inhaled and imaged with a gamma camera.

Krypton-85 in the atmosphere has been used to detect clandestine nuclear fuel reprocessing facilities in North Korea and Pakistan. Those facilities were detected in the early 2000s and were believed to be producing weapons-grade plutonium.

Krypton is used occasionally as an insulating gas between window panes.

SpaceX Starlink use krypton as propellant for their electric propulsion system.

Precautions

Krypton is considered to be a non-toxic asphyxiant. Krypton has a narcotic potency seven times greater than air, and breathing an atmosphere of 50% krypton and 50% natural air (as might happen in the locality of a leak) causes narcosis in humans similar to breathing air at four times atmospheric pressure. This is comparable to scuba diving at a depth of 30 m (100 ft) (see nitrogen narcosis) and could affect anyone breathing it. At the same time, that mixture would contain only 10% oxygen (rather than the normal 20%) and hypoxia would be a greater concern.

References

1. ^ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265-91. doi:10.1515/pac-2015-0305.

2. ^ "Section 4, Properties of the Elements and Inorganic Compounds; Melting, boiling, triple, and critical temperatures of the elements". CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. 2005.

3. ^ Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.121. ISBN 1439855110.

4. ^ Shuen-Chen Hwang, Robert D. Lein, Daniel A. Morgan (2005). "Noble Gases". Kirk Othmer Encyclopedia of Chemical Technology. Wiley. pp. 343-383. doi:10.1002/0471238961.0701190508230114.a01.

5. ^ Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.

6. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

7. ^ Patrignani, C.; et al. (Particle Data Group) (2016). "Review of Particle Physics". Chinese Physics C. 40 (10): 100001. Bibcode:2016ChPhC..40j0001P. doi:10.1088/1674-1137/40/10/100001. See p. 768

8. ^ William Ramsay; Morris W. Travers (1898). "On a New Constituent of Atmospheric Air". Proceedings of the Royal Society of London. 63 (1): 405-408. doi:10.1098/rspl.1898.0051.

9. ^ Burdun, G. D. (1958). "On the new determination of the meter". Measurement Techniques. 1 (3): 259-264. doi:10.1007/BF00974680.

10. ^ Kimothi, Shri Krishna (2002). The uncertainty of measurements: physical and chemical metrology: impact and analysis. American Society for Quality. p. 122. ISBN 978-0-87389-535-4.

11. ^ Gibbs, Philip (1997). "How is the speed of light measured?". Department of Mathematics, University of California. Archived from the original on 2015-08-21.

12. ^ Gavrilyuk, Yu. M.; Gangapshev, A. M.; Kazalov, V. V.; Kuzminov, V. V.; Panasenko, S. I.; Ratkevich, S. S. (4 March 2013). "Indications of 2ν2K capture in ⁷⁸Kr". Phys. Rev. C. 87 (3): 035501. Bibcode:2013PhRvC..87c5501G. doi:10.1103/PhysRevC.87.035501.

13. ^ Thonnard, Norbert; MeKay, Larry D.; Labotka, Theodore C. (2001-02-05). "Development of Laser-Based Resonance Ionization Techniques for 81-Kr and 85-Kr Measurements in the Geosciences" (PDF). University of Tennessee, Institute for Rare Isotope Measurements. pp. 4-7.

14. ^ "Resources on Isotopes". U.S. Geological Survey. Archived from the original on 2001-09-24.

15. ^ Kleppe, Annette K.; Amboage, Mónica; Jephcoat, Andrew P. (2014). "New high-pressure van der Waals compound Kr(H₂)₄ discovered in the krypton-hydrogen binary system". Scientific Reports. 4: 4989. Bibcode:2014NatSR...4E4989K. doi:10.1038/srep04989.

16. ^ Grosse, A. V.; Kirshenbaum, A. D.; Streng, A. G.; Streng, L. V. (1963). "Krypton Tetrafluoride: Preparation and Some Properties". Science. 139 (3559): 1047-1048. Bibcode:1963Sci...139.1047G. doi:10.1126/science.139.3559.1047. PMID 17812982.

17. ^ Lewars, Errol G. (2008). Modeling Marvels: Computational Anticipation of Novel Molecules. Springer. p. 68. ISBN 978-1-4020-6972-7.

18. ^ Cardelli, Jason A.; Meyer, David M. (1996). "The Abundance of Interstellar Krypton". The Astrophysical Journal Letters. 477 (1): L57-L60. Bibcode:1997ApJ...477L..57C. doi:10.1086/310513.

19. ^ Sethian, J.; M. Friedman; M. Myers. "Krypton Fluoride Laser Development for Inertial Fusion Energy" (PDF). Plasma Physics Division, Naval Research Laboratory. pp. 1-8.

20. ^ Pavlovskaya, GE; Cleveland, ZI; Stupic, KF; Basaraba, RJ; et al. (2005). "Hyperpolarized krypton-83 as a contrast agent for magnetic resonance imaging". Proceedings of the National Academy of Sciences of the United States of America. 102 (51): 18275-9. Bibcode:2005PNAS..10218275P. doi:10.1073/pnas.0509419102. PMC . PMID 16344474.

21. ^ Chon, D; Beck, KC; Simon, BA; Shikata, H; et al. (2007). "Effect of low-xenon and krypton supplementation on signal/noise of regional CT-based ventilation measurements". Journal of Applied Physiology. 102 (4): 1535-44. doi:10.1152/japplphysiol.01235.2005. PMID 17122371.

22. ^ Bajc, M.; Neilly, J. B.; Miniati, M.; Schuemichen, C.; Meignan, M.; Jonson, B. (27 June 2009). "EANM guidelines for ventilation/perfusion scintigraphy". European Journal of Nuclear Medicine and Molecular Imaging. 36 (8): 1356-1370. doi:10.1007/s00259-009-1170-5. PMID 19562336.

23. ^ Sanger, David E.; Shanker, Thom (2003-07-20). "N. Korea may be hiding new nuclear site". Oakland Tribune. Archived from the original on 2016-04-09 - via Highbeam Research.

24. ^ Bradley, Ed; Martin, David (2000-03-16). "U.S. Intelligence Find Evidence of Pakistan Producing Nuclear Weapons, CBS". CBS Evening News with Dan Rather. Archived from the original on 2016-10-18 - via Highbeam Research.

25. ^ Ayre, James (2018-04-28). "Insulated Windows 101 - Double Glazing, Triple Glazing, Thermal Performance, & Potential Problems". cleantechnica.com.

26. ^ Properties of Krypton Archived 2009-02-19 at the Wayback Machine. Pt.chemicalstore.com. Retrieved on 2015-11-30.

Further reading

External links

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A krypton-filled discharge tube glowing white Krypton Pronunciation ​(KRIP-ton ) Appearance colorless gas, exhibiting a whitish glow in an electric field Standard atomic weight A r, std(Kr) 83.798(2) [1] Krypton in the periodic table (Atomic number Z) 36 Group group 18 (noble gases) Period period 4 Block p-block Element category Noble gas Electron configuration [ Ar] 3d 10 4s 2 4p 6 Electrons per shell 2, 8, 18, 8 Physical properties at Phase STP gas Melting point 115.78 K ​(−157.37 °C, ​−251.27 °F) Boiling point 119.93 K ​(−153.415 °C, ​−244.147 °F) Density (at STP) 3.749 g/L when liquid (at b.p.)

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krypton <?php print krypton ?> atomic weight

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WebElements Periodic Table " Krypton " the essentials

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This WebElements periodic table page contains the essentials for the element krypton

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Krypton is element number 36. Videos about all the elements at http://www.periodicvideos.com/