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85-408: Hydrogen ( 1 H) has three naturally occurring isotopes : H, H, and H. H and H are stable, while H has a half-life of 12.32(2) years. Heavier isotopes also exist; all are synthetic and have a half-life of less than 1 zeptosecond (10 s). Of these, H is the least stable, while H is the most. Hydrogen is the only element whose isotopes have different names that remain in common use today: H

170-472: A coolant in the rotor and the stator in 1937 at Dayton , Ohio, owned by the Dayton Power & Light Co. This was justified by the high thermal conductivity and very low viscosity of hydrogen gas, thus lower drag than air. This is the most common coolant used for generators 60 MW and larger; smaller generators are usually air-cooled . The nickel–hydrogen battery was used for the first time in 1977 aboard

255-521: A half-life of 86(6)  ys ( 8.6(6) × 10 s ) – the shortest half-life of any known nuclide. H ( atomic mass 6.044 96 (27) ) has one proton and five neutrons . It has a half-life of 294(67)  ys ( 2.94(67) × 10 s ). H ( atomic mass 7.052 75 (108) ) has one proton and six neutrons . It was first synthesized in 2003 by a group of Russian, Japanese and French scientists at Riken 's Radioactive Isotope Beam Factory by bombarding hydrogen with helium-8 atoms; all six of

340-412: A nuclear reactor . Tritium can be used in chemical and biological labeling experiments as a radioactive tracer . Deuterium–tritium fusion uses H and H as its main reactants, giving energy through the loss of mass when the two nuclei collide and fuse at high temperatures. H ( atomic mass 4.026 43 (11) ), with one proton and three neutrons, is a highly unstable isotope. It has been synthesized in

425-465: A nucleus which is usually composed of one proton. That is why H is often called a proton. This species is central to discussion of acids . Under the Brønsted–Lowry acid–base theory , acids are proton donors, while bases are proton acceptors. A bare proton, H , cannot exist in solution or in ionic crystals because of its strong attraction to other atoms or molecules with electrons. Except at

510-490: A stoichiometric quantity of hydrogen at the anode. For hydrides other than group 1 and 2 metals, the term is quite misleading, considering the low electronegativity of hydrogen. An exception in group 2 hydrides is BeH 2 , which is polymeric. In lithium aluminium hydride , the [AlH 4 ] anion carries hydridic centers firmly attached to the Al(III). Although hydrides can be formed with almost all main-group elements,

595-437: A fire. Anaerobic oxidation of iron by the protons of water at high temperature can be schematically represented by the set of following reactions: Many metals such as zirconium undergo a similar reaction with water leading to the production of hydrogen. François Isaac de Rivaz built the first de Rivaz engine , an internal combustion engine powered by a mixture of hydrogen and oxygen in 1806. Edward Daniel Clarke invented

680-430: A half-life of 13.22 hours. The emitted 159  keV gamma ray is used in single-photon emission computed tomography (SPECT). A 127 keV gamma ray is also emitted. I is frequently used in radioimmunoassays because of its relatively long half-life (59 days) and ability to be detected with high sensitivity by gamma counters. I is present in the environment as a result of the testing of nuclear weapons in

765-484: A half-life of 5730 years. It is continuously produced in the upper atmosphere of the earth, so it occurs at a trace level in the environment. However, it is not practical to use naturally-occurring C for tracer studies. Instead it is made by neutron irradiation of the isotope C which occurs naturally in carbon at about the 1.1% level. C has been used extensively to trace the progress of organic molecules through metabolic pathways. N decays by positron emission with

850-403: A half-life of 9.97 min. It is produced by the nuclear reaction N is used in positron emission tomography (PET scan). O decays by positron emission with a half-life of 122 seconds. It is used in positron emission tomography. F decays predominantly by β emission, with a half-life of 109.8 min. It is made by proton bombardment of O in a cyclotron or linear particle accelerator . It

935-473: A half-life of approximately 66 hours (2.75 days), so the generator has a useful life of about two weeks. Most commercial Tc generators use column chromatography , in which Mo in the form of molybdate, MoO 4 is adsorbed onto acid alumina (Al 2 O 3 ). When the Mo decays it forms pertechnetate TcO 4 , which because of its single charge is less tightly bound to the alumina. Pulling normal saline solution through

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1020-510: A half-life: 6.01 hours. The short half-life ensures that the body-concentration of the radioisotope falls effectively to zero in a few days. I is produced by proton irradiation of Xe . The caesium isotope produced is unstable and decays to I. The isotope is usually supplied as the iodide and hypoiodate in dilute sodium hydroxide solution, at high isotopic purity. I has also been produced at Oak Ridge National Laboratories by proton bombardment of Te . I decays by electron capture with

1105-467: A molar basis ) because of its light weight, which enables it to escape the atmosphere more rapidly than heavier gases. However, hydrogen is the third most abundant element on the Earth's surface, mostly in the form of chemical compounds such as hydrocarbons and water. Radioactive tracer Radioisotopes of hydrogen , carbon , phosphorus , sulfur , and iodine have been used extensively to trace

1190-448: A monatomic gas at cryogenic temperatures. According to quantum theory, this behavior arises from the spacing of the (quantized) rotational energy levels, which are particularly wide-spaced in H 2 because of its low mass. These widely spaced levels inhibit equal partition of heat energy into rotational motion in hydrogen at low temperatures. Diatomic gases composed of heavier atoms do not have such widely spaced levels and do not exhibit

1275-455: A number of tests, such as Tc in autoradiography and nuclear medicine , including single-photon emission computed tomography (SPECT), positron emission tomography (PET) and scintigraphy . The urea breath test for helicobacter pylori commonly used a dose of C labeled urea to detect h. pylori infection. If the labeled urea was metabolized by h. pylori in the stomach, the patient's breath would contain labeled carbon dioxide. In recent years,

1360-545: A partial negative charge. These compounds are often known as hydrides . Hydrogen forms many compounds with carbon called the hydrocarbons , and even more with heteroatoms that, due to their association with living things, are called organic compounds . The study of their properties is known as organic chemistry and their study in the context of living organisms is called biochemistry . By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it

1445-477: A partial positive charge. When bonded to a more electronegative element, particularly fluorine , oxygen , or nitrogen , hydrogen can participate in a form of medium-strength noncovalent bonding with another electronegative element with a lone pair, a phenomenon called hydrogen bonding that is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as metals and metalloids , where it takes on

1530-405: A proton and an electron, the hydrogen atom , together with the spectrum of light produced from it or absorbed by it, has been central to the development of the theory of atomic structure. Furthermore, study of the corresponding simplicity of the hydrogen molecule and the corresponding cation H + 2 brought understanding of the nature of the chemical bond , which followed shortly after

1615-526: A serious incident. Hydrogen-lifted airships were used as observation platforms and bombers during the war. The first non-stop transatlantic crossing was made by the British airship R34 in 1919. Regular passenger service resumed in the 1920s and the discovery of helium reserves in the United States promised increased safety, but the U.S. government refused to sell the gas for this purpose. Therefore, H 2

1700-440: A similar experiment with iron and sulfuric acid. However, in all likelihood, "sulfureous" should here be understood to mean "combustible". In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "inflammable air". He speculated that "inflammable air" was in fact identical to the hypothetical substance " phlogiston " and further finding in 1781 that

1785-498: A smaller portion comes from energy-intensive methods such as the electrolysis of water . Its main industrial uses include fossil fuel processing, such as hydrocracking , and ammonia production , with emerging uses in fuel cells for electricity generation and as a heat source. When used in fuel cells, hydrogen's only emission at point of use is water vapor, though combustion can produce nitrogen oxides . Hydrogen's interaction with metals may cause embrittlement . Hydrogen gas

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1870-467: A spark or flame, they do not react at room temperature in the absence of a catalyst. The ground state energy level of the electron in a hydrogen atom is −13.6  eV , equivalent to an ultraviolet photon of roughly 91 nm wavelength. The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, in which the electron "orbits" the proton, like how Earth orbits

1955-450: A species. To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the " hydronium ion" ( [H 3 O] ). However, even in this case, such solvated hydrogen cations are more realistically conceived as being organized into clusters that form species closer to [H 9 O 4 ] . Other oxonium ions are found when water

2040-406: A spin singlet state having spin S = 0 {\displaystyle S=0} . The equilibrium ratio of ortho- to para-hydrogen depends on temperature. At room temperature or warmer, equilibrium hydrogen gas contains about 25% of the para form and 75% of the ortho form. The ortho form is an excited state , having higher energy than the para form by 1.455 kJ/mol, and it converts to

2125-438: A term that is used fairly loosely. The term "hydride" suggests that the H atom has acquired a negative or anionic character, denoted H ; and is used when hydrogen forms a compound with a more electropositive element. The existence of the hydride anion , suggested by Gilbert N. Lewis in 1916 for group 1 and 2 salt-like hydrides, was demonstrated by Moers in 1920 by the electrolysis of molten lithium hydride (LiH), producing

2210-478: A while before caus'd to be purposely fil'd off from a piece of good steel. This metalline powder being moistn'd in the viol with a little of the menstruum, was afterwards drench'd with more; whereupon the mixture grew very hot, and belch'd up copious and stinking fumes; which whether they consisted altogether of the volatile sulfur of the Mars [iron], or of metalline steams participating of a sulfureous nature, and join'd with

2295-883: Is Ga for gallium scans . Ga is used because, like Tc, it is a gamma-ray emitter and various ligands can be attached to the Ga ion, forming a coordination complex which may have selective affinity for particular sites in the human body. An extensive list of radioactive tracers used in hydraulic fracturing can be found below. In metabolism research, tritium and C -labeled glucose are commonly used in glucose clamps to measure rates of glucose uptake , fatty acid synthesis , and other metabolic processes. While radioactive tracers are sometimes still used in human studies, stable isotope tracers such as C are more commonly used in current human clamp studies. Radioactive tracers are also used to study lipoprotein metabolism in humans and experimental animals. In medicine , tracers are applied in

2380-618: Is deuterium and H is tritium . The symbols D and T are sometimes used for deuterium and tritium; IUPAC ( International Union of Pure and Applied Chemistry ) accepts said symbols, but recommends the standard isotopic symbols H and H, to avoid confusion in alphabetic sorting of chemical formulas . H, with no neutrons , may be called protium to disambiguate. (During the early study of radioactivity, some other heavy radioisotopes were given names , but such names are rarely used today.) Note: "y" means year, but "ys" means yoctosecond (10 second). H (atomic mass 1.007 825 031 898 (14)  Da )

2465-579: Is exothermic and produces enough heat to evaporate most of the liquid if not converted first to parahydrogen during the cooling process. Catalysts for the ortho-para interconversion, such as ferric oxide and activated carbon compounds, are used during hydrogen cooling to avoid this loss of liquid. While H 2 is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative , such as halogens (F, Cl, Br, I), or oxygen ; in these compounds hydrogen takes on

2550-425: Is radioactive , β decaying into helium-3 with half-life 12.32(2) years . Traces of H occur naturally due to cosmic rays interacting with atmospheric gases. H has also been released in nuclear tests . It is used in fusion bombs , as a tracer in isotope geochemistry , and in self-powered lighting devices. The most common way to produce H is to bombard a natural isotope of lithium , Li, with neutrons in

2635-406: Is also a beta-emitter, with a half-life of 25.4 days. Though more expensive than P , the emitted electrons are less energetic, permitting better resolution in, for example, DNA sequencing. Both isotopes are useful for labeling nucleotides and other species that contain a phosphate group. S is made by neutron bombardment of Cl It decays by beta-decay with a half-life of 87.51 days. It

Isotopes of hydrogen - Misplaced Pages Continue

2720-467: Is an important isotope in the radiopharmaceutical industry. For example, it is used to make labeled fluorodeoxyglucose (FDG) for application in PET scans. P is made by neutron bombardment of S It decays by beta decay with a half-life of 14.29 days. It is commonly used to study protein phosphorylation by kinases in biochemistry. P is made in relatively low yield by neutron bombardment of P . It

2805-505: Is crucial in acid-base reactions , which mainly involve proton exchange among soluble molecules. In ionic compounds , hydrogen can take the form of either a negatively charged anion , where it is known as hydride , or as a positively charged cation , H . The cation, usually just a proton (symbol p ), exhibits specific behavior in aqueous solutions and in ionic compounds involves screening of its electric charge by surrounding polar molecules or anions. Hydrogen's unique position as

2890-416: Is detected in order to probe primordial hydrogen. The large amount of neutral hydrogen found in the damped Lyman-alpha systems is thought to dominate the cosmological baryonic density of the universe up to a redshift of z  = 4. Under ordinary conditions on Earth, elemental hydrogen exists as the diatomic gas, H 2 . Hydrogen gas is very rare in Earth's atmosphere (around 0.53 ppm on

2975-400: Is highly flammable: Enthalpy of combustion : −286 kJ/mol. Hydrogen gas forms explosive mixtures with air in concentrations from 4–74% and with chlorine at 5–95%. The hydrogen autoignition temperature , the temperature of spontaneous ignition in air, is 500 °C (932 °F). Pure hydrogen-oxygen flames emit ultraviolet light and with high oxygen mix are nearly invisible to

3060-453: Is in acidic solution with other solvents. Although exotic on Earth, one of the most common ions in the universe is the H + 3 ion, known as protonated molecular hydrogen or the trihydrogen cation. Hydrogen has three naturally occurring isotopes, denoted H , H and H . Other, highly unstable nuclei ( H to H ) have been synthesized in the laboratory but not observed in nature. Unique among

3145-473: Is in years. Hydrogen Hydrogen is a chemical element ; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions , is a gas of diatomic molecules with the formula H 2 , sometimes called dihydrogen , but more commonly called hydrogen gas , molecular hydrogen or simply hydrogen. It is colorless, odorless, non-toxic, and highly combustible . Constituting about 75% of all normal matter , hydrogen

3230-540: Is not radioactive, and is not a significant toxicity hazard. Water enriched in H is called heavy water . Deuterium and its compounds are used as a non-radioactive label in chemical experiments and in solvents for H- nuclear magnetic resonance spectroscopy . Heavy water is used as a neutron moderator and coolant for nuclear reactors. Deuterium is also a potential fuel for commercial nuclear fusion . Tritium , H (atomic mass 3.016 049 281 320 (81)  Da ), contains one proton and two neutrons in its nucleus (triton). It

3315-455: Is performed in a nuclear reactor . The other main method used to synthesize radioisotopes is proton bombardment. The proton are accelerated to high energy either in a cyclotron or a linear accelerator . Tritium (hydrogen-3) is produced by neutron irradiation of Li : Tritium has a half-life 4500 ± 8 days (approximately 12.32 years) and it decays by beta decay . The electrons produced have an average energy of 5.7 keV. Because

3400-484: Is soluble in both nanocrystalline and amorphous metals . Hydrogen solubility in metals is influenced by local distortions or impurities in the crystal lattice . These properties may be useful when hydrogen is purified by passage through hot palladium disks, but the gas's high solubility is a metallurgical problem, contributing to the embrittlement of many metals, complicating the design of pipelines and storage tanks. Hydrogen compounds are often called hydrides ,

3485-532: Is still used, in preference to non-flammable but more expensive helium, as a lifting gas for weather balloons . Deuterium was discovered in December 1931 by Harold Urey , and tritium was prepared in 1934 by Ernest Rutherford , Mark Oliphant , and Paul Harteck . Heavy water , which consists of deuterium in the place of regular hydrogen, was discovered by Urey's group in 1932. The first hydrogen-cooled turbogenerator went into service using gaseous hydrogen as

Isotopes of hydrogen - Misplaced Pages Continue

3570-487: Is the most abundant chemical element in the universe . Stars , including the Sun , mainly consist of hydrogen in a plasma state , while on Earth, hydrogen is found in water , organic compounds , as dihydrogen , and in other molecular forms . The most common isotope of hydrogen (protium, H) consists of one proton , one electron , and no neutrons . In the early universe , the formation of hydrogen's protons occurred in

3655-412: Is the carbon-hydrogen bond that gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated pathways that seldom involve elemental hydrogen. Hydrogen is highly soluble in many rare earth and transition metals and

3740-508: Is the most common hydrogen isotope, with an abundance of >99.98%. Its nucleus consists of only a single proton , so it has the formal name protium . The proton has never been observed to decay, so H is considered a stable isotope. Some Grand Unified Theories proposed in the 1970s predict that proton decay can occur with a half-life between 10 and 10 years. If so, then H (and all nuclei now believed to be stable) are only observationally stable . As of 2018, experiments have shown that

3825-455: Is used to label the sulfur-containing amino-acids methionine and cysteine . When a sulfur atom replaces an oxygen atom in a phosphate group on a nucleotide a thiophosphate is produced, so S can also be used to trace a phosphate group. Tc is a very versatile radioisotope, and is the most commonly used radioisotope tracer in medicine. It is easy to produce in a technetium-99m generator , by decay of Mo . The molybdenum isotope has

3910-521: The Big Bang and outer solar system (≈27 ppm, by atom fraction) and older parts of the Milky Way (≈23 ppm). Presumably the differential concentration of deuterium in the inner solar system is due to the lower volatility of deuterium gas and compounds, enriching deuterium fractions in comets and planets exposed to significant heat from the Sun over billions of years of solar system evolution . Deuterium

3995-496: The Hindenburg airship was a notorious example of hydrogen combustion and the cause is still debated. The visible flames in the photographs were the result of carbon compounds in the airship skin burning. H 2 is unreactive compared to diatomic elements such as halogens or oxygen. The thermodynamic basis of this low reactivity is the very strong H–H bond, with a bond dissociation energy of 435.7 kJ/mol. The kinetic basis of

4080-570: The International Union of Pure and Applied Chemistry (IUPAC) allows any of D, T, H , and H to be used, though H and H are preferred. The exotic atom muonium (symbol Mu), composed of an anti muon and an electron , can also be considered a light radioisotope of hydrogen. Because muons decay with lifetime 2.2  µs , muonium is too unstable for observable chemistry. Nevertheless, muonium compounds are important test cases for quantum simulation , due to

4165-431: The "planetary orbit" differs from electron motion. Molecular H 2 exists as two spin isomers , i.e. compounds that differ only in the spin states of their nuclei. In the orthohydrogen form, the spins of the two nuclei are parallel, forming a spin triplet state having a total molecular spin S = 1 {\displaystyle S=1} ; in the parahydrogen form the spins are antiparallel and form

4250-428: The 1943 Nobel Prize for Chemistry "for his work on the use of isotopes as tracers in the study of chemical processes". There are two main ways in which radioactive tracers are used The commonly used radioisotopes have short half lives and so do not occur in nature in large amounts. They are produced by nuclear reactions . One of the most important processes is absorption of a neutron by an atomic nucleus, in which

4335-513: The Duchy of Grand Fenwick captured from the United States. H ( atomic mass 5.035 31 (10) ), with one proton and four neutrons, is highly unstable. It has been synthesized in the lab by bombarding tritium with fast-moving tritons; one triton captures two neutrons from the other, becoming a nucleus with one proton and four neutrons. The remaining proton may be detected, and the existence of H deduced. It decays by double neutron emission into H and has

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4420-476: The Sun and other stars). The charged particles are highly influenced by magnetic and electric fields. For example, in the solar wind they interact with the Earth's magnetosphere giving rise to Birkeland currents and the aurora . Hydrogen is found in the neutral atomic state in the interstellar medium because the atoms seldom collide and combine. They are the source of the 21-cm hydrogen line at 1420 MHz that

4505-454: The Sun and the CNO cycle of nuclear fusion in case of stars more massive than the Sun . Throughout the universe, hydrogen is mostly found in the atomic and plasma states, with properties quite distinct from those of molecular hydrogen. As a plasma, hydrogen's electron and proton are not bound together, resulting in very high electrical conductivity and high emissivity (producing the light from

4590-460: The Sun. However, the electron and proton are held together by electrostatic attraction, while planets and celestial objects are held by gravity . Due to the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies. A more accurate description of

4675-641: The U.S. Navy's Navigation technology satellite-2 (NTS-2). The International Space Station , Mars Odyssey and the Mars Global Surveyor are equipped with nickel-hydrogen batteries. In the dark part of its orbit, the Hubble Space Telescope is also powered by nickel-hydrogen batteries, which were finally replaced in May 2009, more than 19 years after launch and 13 years beyond their design life. Because of its simple atomic structure, consisting only of

4760-482: The atmosphere. It was also produced in the Chernobyl and Fukushima disasters. I decays with a half-life of 15.7 million years, with low-energy beta and gamma emissions. It is not used as a tracer, though its presence in living organisms, including human beings, can be characterized by measurement of the gamma rays. Many other isotopes have been used in specialized radiopharmacological studies. The most widely used

4845-450: The column of immobilized Mo elutes the soluble Tc, resulting in a saline solution containing the Tc as the dissolved sodium salt of the pertechnetate. The pertechnetate is treated with a reducing agent such as Sn and a ligand . Different ligands form coordination complexes which give the technetium enhanced affinity for particular sites in the human body. Tc decays by gamma emission, with

4930-430: The elements, distinct names are assigned to its isotopes in common use. During the early study of radioactivity, heavy radioisotopes were given their own names, but these are mostly no longer used. The symbols D and T (instead of H and H ) are sometimes used for deuterium and tritium, but the symbol P was already used for phosphorus and thus was not available for protium. In its nomenclatural guidelines,

5015-423: The emitted electrons have relatively low energy, the detection efficiency by scintillation counting is rather low. However, hydrogen atoms are present in all organic compounds, so tritium is frequently used as a tracer in biochemical studies. C decays by positron emission with a half-life of ca. 20 min. C is one of the isotopes often used in positron emission tomography . C decays by beta decay , with

5100-493: The first reliable form of air-travel following the 1852 invention of the first hydrogen-lifted airship by Henri Giffard . German count Ferdinand von Zeppelin promoted the idea of rigid airships lifted by hydrogen that later were called Zeppelins ; the first of which had its maiden flight in 1900. Regularly scheduled flights started in 1910 and by the outbreak of World War I in August 1914, they had carried 35,000 passengers without

5185-441: The first second after the Big Bang ; neutral hydrogen atoms only formed about 370,000 years later during the recombination epoch as the universe cooled and plasma had cooled enough for electrons to remain bound to protons. Hydrogen, typically nonmetallic except under extreme pressure , readily forms covalent bonds with most nonmetals, contributing to the formation of compounds like water and various organic substances. Its role

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5270-462: The gas produces water when burned. He is usually given credit for the discovery of hydrogen as an element. In 1783, Antoine Lavoisier identified the element that came to be known as hydrogen when he and Laplace reproduced Cavendish's finding that water is produced when hydrogen is burned. Lavoisier produced hydrogen for his experiments on mass conservation by reacting a flux of steam with metallic iron through an incandescent iron tube heated in

5355-578: The helium-8's neutrons were donated to the hydrogen nucleus. The two remaining protons were detected by the "RIKEN telescope", a device made of several layers of sensors, positioned behind the target of the RI Beam cyclotron. H has a half-life of 652(558)  ys ( 6.52(558) × 10 s ). H and H decay directly to H, which then decays to stable He . Decay of the heaviest isotopes, H and H, has not been experimentally observed. Decay times are in yoctoseconds ( 10 s ) for all these isotopes except H, which

5440-427: The high temperatures associated with plasmas, such protons cannot be removed from the electron clouds of atoms and molecules, and will remain attached to them. However, the term 'proton' is sometimes used loosely and metaphorically to refer to positively charged or cationic hydrogen attached to other species in this fashion, and as such is denoted " H " without any implication that any single protons exist freely as

5525-497: The hydrogen atom comes from a quantum analysis that uses the Schrödinger equation , Dirac equation or Feynman path integral formulation to calculate the probability density of the electron around the proton. The most complex formulas include the small effects of special relativity and vacuum polarization . In the quantum mechanical treatment, the electron in a ground state hydrogen atom has no angular momentum—illustrating how

5610-399: The hydrogen gas blowpipe in 1819. The Döbereiner's lamp and limelight were invented in 1823. Hydrogen was liquefied for the first time by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask . He produced solid hydrogen the next year. The first hydrogen-filled balloon was invented by Jacques Charles in 1783. Hydrogen provided the lift for

5695-461: The laboratory by bombarding tritium with fast-moving deuterons; the triton captured a neutron from the deuteron. The presence of H was deduced by detecting the emitted protons. It decays by neutron emission into H with a half-life of 139(10)  ys (or 1.39(10) × 10 s ). In the 1955 satirical novel The Mouse That Roared , the name quadium was given to the H that powered the Q-bomb that

5780-400: The low reactivity is the nonpolar nature of H 2 and its weak polarizability. It spontaneously reacts with chlorine and fluorine to form hydrogen chloride and hydrogen fluoride , respectively. The reactivity of H 2 is strongly affected by the presence of metal catalysts. Thus, while mixtures of H 2 with O 2 or air combust readily when heated to at least 500°C by

5865-402: The mass difference between the antimuon and the proton, and IUPAC nomenclature incorporates such hypothetical compounds as muonium chloride (MuCl) and sodium muonide (NaMu), analogous to hydrogen chloride and sodium hydride respectively. Table of thermal and physical properties of hydrogen (H 2 ) at atmospheric pressure: In 1671, Irish scientist Robert Boyle discovered and described

5950-405: The mass number of the element concerned increases by 1 for each neutron absorbed. For example, In this case the atomic mass increases, but the element is unchanged. In other cases the product nucleus is unstable and decays, typically emitting protons, electrons ( beta particle ) or alpha particles . When a nucleus loses a proton the atomic number decreases by 1. For example, Neutron irradiation

6035-481: The mass of the universe, however, is not in the form of chemical-element type matter, but rather is postulated to occur as yet-undetected forms of mass such as dark matter and dark energy . Hydrogen is found in great abundance in stars and gas giant planets. Molecular clouds of H 2 are associated with star formation . Hydrogen plays a vital role in powering stars through the proton-proton reaction in case of stars with very low to approximately 1 mass of

6120-494: The mean lifetime of the proton is > 3.6 × 10 years. Deuterium , H (atomic mass 2.014 101 777 844 (15)  Da ), the other stable hydrogen isotope, has one proton and one neutron in its nucleus, called a deuteron. H comprises 26–184 ppm (by population, not mass) of hydrogen on Earth; the lower number tends to be found in hydrogen gas and the higher enrichment (150 ppm) is typical of seawater . Deuterium on Earth has been enriched with respect to its initial concentration in

6205-490: The naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine , compared to the highly visible plume of a Space Shuttle Solid Rocket Booster , which uses an ammonium perchlorate composite . The detection of a burning hydrogen leak, may require a flame detector ; such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames. The destruction of

6290-442: The naturally occurring carbon-14 isotope as an isotopic label . Isotopes of a chemical element differ only in the mass number. For example, the isotopes of hydrogen can be written as H , H and H , with the mass number superscripted to the left. When the atomic nucleus of an isotope is unstable, compounds containing this isotope are radioactive . Tritium is an example of a radioactive isotope. The principle behind

6375-649: The number and combination of possible compounds varies widely; for example, more than 100 binary borane hydrides are known, but only one binary aluminium hydride. Binary indium hydride has not yet been identified, although larger complexes exist. In inorganic chemistry , hydrides can also serve as bridging ligands that link two metal centers in a coordination complex . This function is particularly common in group 13 elements , especially in boranes ( boron hydrides) and aluminium complexes, as well as in clustered carboranes . Oxidation of hydrogen removes its electron and gives H , which contains no electrons and

6460-651: The only neutral atom for which the Schrödinger equation can be directly solved, has significantly contributed to the foundational principles of quantum mechanics through the exploration of its energetics and chemical bonding . Hydrogen gas was first produced artificially in the early 16th century by reacting acids with metals. Henry Cavendish , in 1766–81, identified hydrogen gas as a distinct substance and discovered its property of producing water when burned; hence its name means "water-former" in Greek. Most hydrogen production occurs through steam reforming of natural gas ;

6545-420: The para form over the course of several minutes when cooled to low temperature. The thermal properties of the forms differ because they differ in their allowed rotational quantum states , resulting in different thermal properties such as the heat capacity. The ortho-to-para ratio in H 2 is an important consideration in the liquefaction and storage of liquid hydrogen : the conversion from ortho to para

6630-504: The path of biochemical reactions . A radioactive tracer can also be used to track the distribution of a substance within a natural system such as a cell or tissue , or as a flow tracer to track fluid flow . Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production. Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans , SPECT scans and technetium scans . Radiocarbon dating uses

6715-477: The quantum mechanical treatment of the hydrogen atom had been developed in the mid-1920s. One of the first quantum effects to be explicitly noticed (but not understood at the time) was a Maxwell observation involving hydrogen, half a century before full quantum mechanical theory arrived. Maxwell observed that the specific heat capacity of H 2 unaccountably departs from that of a diatomic gas below room temperature and begins to increasingly resemble that of

6800-502: The reaction between iron filings and dilute acids , which results in the production of hydrogen gas. Having provided a saline spirit [hydrochloric acid], which by an uncommon way of preparation was made exceeding sharp and piercing, we put into a vial, capable of containing three or four ounces of water, a convenient quantity of filings of steel, which were not such as are commonly sold in shops to Chymists and Apothecaries, (those being usually not free enough from rust) but such as I had

6885-506: The saline exhalations of the menstruum, is not necessary to be here discuss'd. But whencesoever this stinking smoak proceeded, so inflammable it was, that upon the approach of a lighted candle to it, it would readily enough take fire, and burn with a blewish and somewhat greenish flame at the mouth of the viol for a good while together; and that, though with little light, yet with more strength than one would easily suspect. The word "sulfureous" may be somewhat confusing, especially since Boyle did

6970-405: The same effect. Antihydrogen ( H ) is the antimatter counterpart to hydrogen. It consists of an antiproton with a positron . Antihydrogen is the only type of antimatter atom to have been produced as of 2015 . Hydrogen, as atomic H, is the most abundant chemical element in the universe, making up 75% of normal matter by mass and >90% by number of atoms. Most of

7055-569: The use of radioactive tracers is that an atom in a chemical compound is replaced by another atom, of the same chemical element. The substituting atom, however, is a radioactive isotope. This process is often called radioactive labeling. The power of the technique is due to the fact that radioactive decay is much more energetic than chemical reactions. Therefore, the radioactive isotope can be present in low concentration and its presence detected by sensitive radiation detectors such as Geiger counters and scintillation counters . George de Hevesy won

7140-404: The use of substances enriched in the non-radioactive isotope C has become the preferred method, avoiding patient exposure to radioactivity. In hydraulic fracturing , radioactive tracer isotopes are injected with hydraulic fracturing fluid to determine the injection profile and location of created fractures. Tracers with different half-lives are used for each stage of hydraulic fracturing. In

7225-521: Was used in the Hindenburg airship, which was destroyed in a midair fire over New Jersey on 6 May 1937. The incident was broadcast live on radio and filmed. Ignition of leaking hydrogen is widely assumed to be the cause, but later investigations pointed to the ignition of the aluminized fabric coating by static electricity . But the damage to hydrogen's reputation as a lifting gas was already done and commercial hydrogen airship travel ceased . Hydrogen

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