Isotopes of hydrogen - wikipedia Isotopes of hydrogen The three most stable isotopes of hydrogen : protium ( A = 1 ), deuterium ( A = 2 ), and tritium ( A = 3 ). Main isotopes of hydrogen Isotope Decay abundance half - life ( t ) mode product 99.98 % stable 0.02 % stable trace 12.32 y β He Standard atomic weight ( A ) ( 7000100784000000000 ♠ 1.007 84, 7000100811000000000 ♠ 1.008 11 ) Conventional : 1.008 view talk Hydrogen ( H ) has three naturally occurring isotopes, sometimes denoted H, H, and H. The first two of these are stable while H has a half - life of 12.32 years. All heavier isotopes are synthetic and have a half - life less than one zeptosecond ( 10 second ). Of these, H is the most stable, and H is the least. Hydrogen is the only element whose isotopes have different names that are in common use today. The H ( or hydrogen - 2 ) isotope is usually called deuterium, while the H ( or hydrogen - 3 ) isotope is usually called tritium. The symbols D and T ( instead of H and H ) are sometimes used for deuterium and tritium. The IUPAC states in the 2005 Red Book that while the use of D and T is common, it is not preferred because it can cause problems in the alphabetic sorting of chemical formulas. The ordinary isotope of hydrogen, with no neutrons, is sometimes called `` protium ''. ( During the early study of radioactivity, some other heavy radioactive isotopes were given names, but such names are rarely used today. ) Contents 1 Hydrogen - 1 ( protium ) 2 Hydrogen - 2 ( deuterium ) 3 Hydrogen - 3 ( tritium ) 4 Hydrogen - 4 5 Hydrogen - 5 6 Hydrogen - 6 7 Hydrogen - 7 8 List of isotopes 8.1 Notes 9 Decay chains 10 See also 11 References 12 Further reading Hydrogen - 1 ( protium ) Protium, the most common isotope of hydrogen, consists of one proton and one electron. Unique among all stable isotopes, it has no neutrons. ( see diproton for a discussion of why others do not exist ) For more details on this topic, see hydrogen atom. H ( atomic mass 7000100782503224100 ♠ 1.007 825 032 241 ( 94 ) u ) is the most common hydrogen isotope with an abundance of more than 99.98 %. Because the nucleus of this isotope consists of only a single proton, it is given the formal name protium. The proton has never been observed to decay, and hydrogen - 1 is therefore 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 this prediction is found to be true, then hydrogen - 1 ( and indeed all nuclei now believed to be stable ) are only observationally stable. To date, however, experiments have shown that the minimum proton half - life is in excess of 10 years. Hydrogen - 2 ( deuterium ) For more details on this topic, see deuterium. A deuterium atom contains one proton, one neutron, and one electron H ( atomic mass 7000201410177811000 ♠ 2.014 101 778 11 ( 12 ) u ), the other stable hydrogen isotope, is known as deuterium and contains one proton and one neutron in its nucleus. The nucleus of deuterium is called a deuteron. Deuterium comprises 0.0026 -- 0.0184 % ( by population, not by mass ) of hydrogen samples on Earth, with the lower number tending to be found in samples of hydrogen gas and the higher enrichment ( 0.015 % or 150 ppm ) typical of ocean water. Deuterium on Earth has been enriched with respect to its initial concentration in the Big Bang and the outer solar system ( about 27 ppm, by atom fraction ) and its concentration in older parts of the Milky Way galaxy ( about 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 is not radioactive, and does not represent a significant toxicity hazard. Water enriched in molecules that include deuterium instead of protium is called heavy water. Deuterium and its compounds are used as a non-radioactive label in chemical experiments and in solvents for H - NMR spectroscopy. Heavy water is used as a neutron moderator and coolant for nuclear reactors. Deuterium is also a potential fuel for commercial nuclear fusion. Hydrogen - 3 ( tritium ) For more details on this topic, see tritium. A tritium atom contains one proton, two neutrons, and one electron H ( atomic mass 7000301604928199000 ♠ 3.016 049 281 99 ( 23 ) u ) is known as tritium and contains one proton and two neutrons in its nucleus. It is radioactive, decaying into helium - 3 through β − decay with a half - life of 12.32 years. Trace amounts of tritium occur naturally because of the interaction of cosmic rays with atmospheric gases. Tritium has also been released during nuclear weapons tests. It is used in thermonuclear fusion weapons, as a tracer in isotope geochemistry, and specialized in self - powered lighting devices. The most common method of producing tritium is by bombarding a natural isotope of lithium, lithium - 6, with neutrons in a nuclear reactor. Tritium was once used routinely in chemical and biological labeling experiments as a radiolabel, which has become less common in recent times. D-T nuclear fusion uses tritium as its main reactant, along with deuterium, liberating energy through the loss of mass when the two nuclei collide and fuse at high temperatures. Hydrogen - 4 H ( atomic mass is 7000402643000000000 ♠ 4.026 43 ( 11 ) u ) contains one proton and three neutrons in its nucleus. It is a highly unstable isotope of hydrogen. It has been synthesised in the laboratory by bombarding tritium with fast - moving deuterium nuclei. In this experiment, the tritium nucleus captured a neutron from the fast - moving deuterium nucleus. The presence of the hydrogen - 4 was deduced by detecting the emitted protons. It decays through neutron emission into hydrogen - 3 ( tritium ) with a half - life of about 139 ± 10 yoctoseconds, or ( 1.39 ± 0.10 ) × 10 seconds. In the 1955 satirical novel The Mouse That Roared, the name quadium was given to the hydrogen - 4 isotope that powered the Q - bomb that the Duchy of Grand Fenwick captured from the United States. Hydrogen - 5 H is a highly unstable isotope of hydrogen. The nucleus consists of a proton and four neutrons. It has been synthesised in the laboratory by bombarding tritium with fast - moving tritium nuclei. In this experiment, one tritium nucleus 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 hydrogen - 5 deduced. It decays through double neutron emission into hydrogen - 3 ( tritium ) and has a half - life of at least 910 yoctoseconds ( 9.1 × 10 seconds ). Hydrogen - 6 H decays either through triple neutron emission into hydrogen - 3 ( tritium ) or quadruple neutron emission into hydrogen - 2 ( deuterium ) and has a half - life of 290 yoctoseconds ( 2.9 × 10 seconds ). Hydrogen - 7 H consists of a proton and six neutrons. It was first synthesised 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. In the resulting reaction, all six of the helium - 8 's neutrons were donated to the hydrogen 's nucleus. The two remaining protons were detected by the `` RIKEN telescope '', a device composed of several layers of sensors, positioned behind the target of the RI Beam cyclotron. Hydrogen - 7 has a half life of 23 yoctoseconds ( 2.3 × 10 seconds ). List of isotopes nuclide symbol Z ( p ) N ( n ) isotopic mass ( u ) half - life decay mode ( s ) Daughter Isotope ( s ) nuclear spin representative isotopic composition ( mole fraction ) range of natural variation ( mole fraction ) 0 7000100782503224000 ♠ 1.007 825 032 24 ( 9 ) Stable ⁄ 6999999885000000000 ♠ 0.999 885 ( 70 ) 6999999816000000000 ♠ 0.999 816 -- 6999999974000000000 ♠ 0.999 974 H ( D ) 7000201410177811000 ♠ 2.014 101 778 11 ( 12 ) Stable 6996115000000000000 ♠ 0.000 115 ( 70 ) 6995259999999999999 ♠ 0.000 026 -- 6996184000000000000 ♠ 0.000 184 H ( T ) 7000301604928199000 ♠ 3.016 049 281 99 ( 23 ) 7008388789632000000 ♠ 12.32 ( 2 ) y β He ⁄ Trace 7000402643000000000 ♠ 4.026 43 ( 11 ) 6978139000000000000 ♠ 1.39 ( 10 ) × 10 s ( 6987737001184020000 ♠ 4.6 ( 9 ) MeV ) n 5 7000503531000000000 ♠ 5.035 31 ( 10 ) > 6978910000000000000 ♠ 9.1 × 10 s ? 2n ( ⁄ ) 6 5 7000604496000000000 ♠ 6.044 96 ( 27 ) 6978290000000000000 ♠ 2.90 ( 70 ) × 10 s ( 6987256348237920000 ♠ 1.6 ( 4 ) MeV ) 3n 2 # 4n 7 6 7000705275000000000 ♠ 7.052 75 ( 108 ) # 6977229999999999999 ♠ 2.3 ( 6 ) × 10 s # 4n ⁄ # Jump up ^ Bold for stable isotopes Jump up ^ Refers to that in water. Jump up ^ Greater than 7041347133600000000 ♠ 1.1 × 10 yr. See proton decay. Jump up ^ This and He are the only stable nuclides with more protons than neutrons. Jump up ^ Produced during Big Bang nucleosynthesis Jump up ^ Tank hydrogen has a 2 abundance as low as 6995320000000000000 ♠ 3.2 × 10 ( mole fraction ). Jump up ^ Produced during Big Bang nucleosynthesis, but not primordial, as all such atoms have since decayed to He Jump up ^ Cosmogenic Notes Commercially available materials may have been subjected to an undisclosed or inadvertent isotopic fractionation. Substantial deviations from the given mass and composition can occur. Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties. Isotope abundances are given by IUPAC Commission on Isotopic Abundances and Atomic Weights ( CIAAW ) Decay chains The majority of heavy hydrogen isotopes decay directly to H, which then decays to the stable isotope He. However, H has occasionally been observed to decay directly to stable H. 1 3 H → 12.32 y 2 3 H e + e − ( displaystyle mathrm ( ( ) _ ( 1 ) ^ ( 3 ) H ) ( \xrightarrow ( mathrm ( 12.32 y ) ) ) mathrm ( ( ) _ ( 2 ) ^ ( 3 ) He ) + mathrm ( e ( ) _ ( ) ^ ( - ) ) ) 1 4 H → 139 y s 1 3 H + 0 1 n ( displaystyle mathrm ( ( ) _ ( 1 ) ^ ( 4 ) H ) ( \xrightarrow ( mathrm ( 139 ys ) ) ) mathrm ( ( ) _ ( 1 ) ^ ( 3 ) H ) + mathrm ( ( ) _ ( 0 ) ^ ( 1 ) n ) ) 1 5 H → > 910 y s 1 3 H + 2 0 1 n ( displaystyle mathrm ( ( ) _ ( 1 ) ^ ( 5 ) H ) ( \xrightarrow ( mathrm ( > 910 ys ) ) ) mathrm ( ( ) _ ( 1 ) ^ ( 3 ) H ) + mathrm ( 2 ( ) _ ( 0 ) ^ ( 1 ) n ) ) 1 6 H → 290 y s 1 3 H + 3 0 1 n ( displaystyle mathrm ( ( ) _ ( 1 ) ^ ( 6 ) H ) ( \xrightarrow ( mathrm ( 290 ys ) ) ) mathrm ( ( ) _ ( 1 ) ^ ( 3 ) H ) + mathrm ( 3 ( ) _ ( 0 ) ^ ( 1 ) n ) ) 1 6 H → 290 y s 1 2 H + 4 0 1 n ( displaystyle mathrm ( ( ) _ ( 1 ) ^ ( 6 ) H ) ( \xrightarrow ( mathrm ( 290 ys ) ) ) mathrm ( ( ) _ ( 1 ) ^ ( 2 ) H ) + mathrm ( 4 ( ) _ ( 0 ) ^ ( 1 ) n ) ) 1 7 H → 23 y s 1 3 H + 4 0 1 n ( displaystyle mathrm ( ( ) _ ( 1 ) ^ ( 7 ) H ) ( \xrightarrow ( mathrm ( 23 ys ) ) ) mathrm ( ( ) _ ( 1 ) ^ ( 3 ) H ) + mathrm ( 4 ( ) _ ( 0 ) ^ ( 1 ) n ) ) Note that the decay times are in yoctoseconds for all isotopes except H, which is expressed in years. See also Book : Hydrogen Hydrogen isotope biogeochemistry Muonium References Notes Jump up ^ Meija, J. ; et al. ( 2016 ). `` Atomic weights of the elements 2013 ( IUPAC Technical Report ) ''. Pure Appl. Chem. 88 ( 3 ) : 265 -- 91. doi : 10.1515 / pac - 2015 - 0305. Jump up ^ Y.B. Gurov ; et al. ( 2004 ). `` Spectroscopy of superheavy hydrogen isotopes in stopped - pion absorption by nuclei ''. Physics of Atomic Nuclei. 68 ( 3 ) : 491 -- 497. Bibcode : 2005PAN... 68... 491G. doi : 10.1134 / 1.1891200. ^ Jump up to : A.A. Korsheninnikov ; et al. ( 2003 ). `` Experimental Evidence for the Existence of H and for a Specific Structure of He ''. Physical Review Letters. 90 ( 8 ) : 082501. Bibcode : 2003PhRvL... 90h2501K. doi : 10.1103 / PhysRevLett. 90.082501. Jump up ^ G.L. Miessler ; D.A. Tarr ( 2004 ). Inorganic Chemistry ( 3rd ed. ). Pearson Prentice Hall. ISBN 978 - 0 - 13 - 035471 - 6. ^ Jump up to : G.M. Ter - Akopian ; et al. ( 2002 ). `` Hydrogen - 4 and Hydrogen - 5 from t + t and t + d transfer reactions studied with a 57.5 - MeV triton beam ''. AIP Conference Proceedings. 610 : 920. doi : 10.1063 / 1.1470062. ^ Jump up to : G. Audi ; A.H. Wapstra ; C. Thibault ; J. Blachot ; O. Bersillon ( 2003 ). `` The NUBASE evaluation of nuclear and decay properties '' ( PDF ). Nuclear Physics A. 729 : 3 -- 128. Bibcode : 2003NuPhA. 729... 3A. doi : 10.1016 / j. nuclphysa. 2003.11. 001. Jump up ^ A.A. Korsheninnikov ; et al. ( 2001 ). `` Superheavy Hydrogen H ''. Physical Review Letters. 87 ( 9 ) : 92501. Bibcode : 2001PhRvL... 87i2501K. doi : 10.1103 / PhysRevLett. 87.092501. Jump up ^ http://www.nucleonica.net/unc.aspx General references Isotope masses from : W.J. Huang ; G. Audi ; M. Wang ; F.G. Kondev ; S. Naimi ; X. Xu ( 2017 ). `` The Ame2016 atomic mass evaluation ( I ). Evaluation of input data ; and adjustment procedures '' ( PDF ). Chinese Physics C. 41 ( 3 ) : 7. Bibcode : 2017ChPhC... 41c0002H. doi : 10.1088 / 1674 - 1137 / 41 / 3 / 030002. M. Wang ; G. Audi ; F.G. Kondev ; W.J. Huang ; S. Naimi ; X. Xu ( 2017 ). `` The Ame2016 atomic mass evaluation ( II ). Tables, graphs, and references '' ( PDF ). Chinese Physics C. 41 ( 3 ) : 7. Bibcode : 2017ChPhC... 41c0003W. doi : 10.1088 / 1674 - 1137 / 41 / 3 / 030003. Isotopic compositions and standard atomic masses from : J.R. de Laeter ; J.K. Böhlke ; P. De Bièvre ; H. Hidaka ; H.S. Peiser ; K.J.R. Rosman ; P.D.P. Taylor ( 2003 ). `` Atomic weights of the elements. Review 2000 ( IUPAC Technical Report ) ''. Pure and Applied Chemistry. 75 ( 6 ) : 683 -- 800. doi : 10.1351 / pac200375060683. M.E. Wieser ( 2006 ). `` Atomic weights of the elements 2005 ( IUPAC Technical Report ) ''. Pure and Applied Chemistry. 78 ( 11 ) : 2051 -- 2066. doi : 10.1351 / pac200678112051. Lay summary. Half - life, spin, and isomer data selected from the following sources. See editing notes on this article 's talk page. G. Audi ; A.H. Wapstra ; C. Thibault ; J. Blachot ; O. Bersillon ( 2003 ). `` The NUBASE evaluation of nuclear and decay properties '' ( PDF ). Nuclear Physics A. 729 : 3 -- 128. Bibcode : 2003NuPhA. 729... 3A. doi : 10.1016 / j. nuclphysa. 2003.11. 001. Archived from the original ( PDF ) on 2008 - 09 - 23. National Nuclear Data Center. `` NuDat 2.1 database ''. Brookhaven National Laboratory. Retrieved 23 February 2017. N.E. Holden ( 2004 ). `` Table of the Isotopes ''. In D.R. Lide. CRC Handbook of Chemistry and Physics ( 85th ed. ). CRC Press. Section 11. ISBN 978 - 0 - 8493 - 0485 - 9. Further reading Wikimedia Commons has media related to Isotopes of hydrogen. B. Dumé ( 7 March 2003 ). `` Hydrogen - 7 makes its debut ''. Physics World. Neutron Isotopes of hydrogen Isotopes of helium Table of nuclides Isotopes of the chemical elements He Li Be 5 6 7 8 9 10 Ne 11 Na 12 Mg 13 Al 14 Si 15 16 17 Cl 18 Ar 19 20 Ca 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Kr 37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 54 Xe 55 Cs 56 Ba 57 La 72 Hf 73 Ta 74 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rn 87 Fr 88 Ra 89 Ac 104 Rf 105 Db 106 Sg 107 Bh 108 Hs 109 Mt 110 Ds 111 Rg 112 Cn 113 Nh 114 Fl 115 Mc 116 Lv 117 Ts 118 Og 58 Ce 59 Pr 60 Nd 61 Pm 62 Sm 63 Eu 64 Gd 65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Lu 90 Th 91 Pa 92 U 93 Np 94 Pu 95 Am 96 Cm 97 Bk 98 Cf 99 Es 100 Fm 101 Md 102 No 103 Lr Table of nuclides Categories : Isotopes Tables of nuclides Metastable isotopes Isotopes by element GND : 4189274 - 4 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Isotopes_of_hydrogen&oldid=806397643 '' Categories : Hydrogen Isotopes of hydrogen Lists of isotopes by element Hidden categories : Wikipedia articles with GND identifiers Talk Contents About Wikipedia Asturianu বাংলা Català Чӑвашла Čeština Eesti Español Esperanto Euskara فارسی Français 한국어 हिन्दी Íslenska Italiano Magyar Nederlands 日本 語 ਪੰਜਾਬੀ Polski Português Русский Simple English Slovenščina Svenska ไทย Türkçe Українська Tiếng Việt 吴语 粵語 中文 Edit links This page was last edited on 21 October 2017, at 19 : 30. 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Question: what is the mass number of hydrogen isotope that contains 2 neutrons
Answer: 3.01604928199(23) u; 7000301604928199000♠3.01604928199(23) u); 3.01604928199(23) u; 3.01604928199(23) u; 3.01604928199(23) u