Index to isotope pages
Encyclopedia
| 1 H Isotopes of hydrogen Hydrogen has three naturally occurring isotopes, sometimes denoted 1H, 2H, and 3H. Other, highly unstable nuclei have been synthesized in the laboratory but not observed in nature. The most stable radioisotope is tritium, with a half-life of 12.32 years... |
2 He Isotopes of helium Although there are eight known isotopes of helium , only helium-3 and helium-4 are stable. All radioisotopes are short-lived, the longest-lived being 6He with a half-life of 806.7 milliseconds. The least stable is the diproton, with a half-life of 3x10-27 seconds, even shorter than that of 5He... |
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| 3 Li Isotopes of lithium Naturally occurring lithium is composed of two stable isotopes, and , the latter being the more abundant... |
4 Be Isotopes of beryllium Although beryllium has 12 known isotopes, only one of these isotopes is stable and a primordial nuclide. As such, it is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes are short-lived that none are primordial and their abundance is very low... |
5 B Isotopes of boron Boron naturally occurs in two isotopes, 10B and 11B, the later of which makes up about 80% of natural boron. 14 radioisotopes have been discovered, with mass numbers from 6 to 21, all with short half-lives, the longest being that of 8B, with a half-life of only 770 ms and 12B with a half-life of... |
6 C |
7 N Isotopes of nitrogen Natural Nitrogen consists of two stable isotopes, nitrogen-14, which makes up the vast majority of naturally occurring nitrogen, and nitrogen-15. Fourteen radioactive isotopes have also been found so far, with atomic masses ranging from 10 to 25, and one nuclear isomer, 11mN... |
8 O Isotopes of oxygen There are three stable isotopes of oxygen that lead to oxygen having a standard atomic mass of 15.9994 u. 17 radioactive isotopes have also been characterized, with mass numbers from 12O to 28O, all short-lived, with the longest-lived being 15O with a half-life of 122.24 seconds... |
9 F Isotopes of fluorine Although fluorine has 18 known isotopes from 14F to 31F and one isomer , only one of these isotopes is stable, that is, fluorine-19; as such, it is a monoisotopic element. The longest-lived radioisotope is 18F with a half-life of 109.771 minutes... |
10 Ne Isotopes of neon Neon possesses three stable isotopes, 20Ne, 21Ne, and 22Ne. In addition, 16 radioactive isotopes have been discovered ranging from 16Ne to 34Ne, all short-lived. The longest-lived is 24Ne with a half-life of 3.38 minutes. All others are under a minute, most under a second. The least stable is... |
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| 11 Na Isotopes of sodium There are twenty recognized isotopes of sodium ranging from 18Na to 37Na and two isomers . 23Na is the only stable isotope. As such, it is considered a monoisotopic element and it has a standard atomic mass: 22.98976928 u. Sodium has two radioactive cosmogenic isotopes... |
12 Mg Isotopes of magnesium Magnesium naturally occurs in three stable isotopes, 24Mg, 25Mg, and 26Mg. 19 radioisotopes have been discovered, ranging from 19Mg to 40Mg. The longest-lived radioisotope is 28Mg with a half-life of 20.915 hours. The lighter isotopes mostly decay to isotopes of sodium while the heavier isotopes... |
13 Al Isotopes of aluminium Aluminium has 22 known isotopes from 21Al to 42Al and 4 known isomers. Only 27Al and 26Al occur naturally, however 27Al has a natural abundance of 99.9+ %. Other than 26Al, all radioisotopes have half-lives under 7 minutes, most under a second. Standard atomic mass is 26.9815386 u... |
14 Si Isotopes of silicon Silicon has 24 known isotopes, with mass numbers ranging from 22 to 45. 28Si , 29Si , and 30Si are stable. The longest-lived radioisotope is 32Si, which is produced by cosmic ray spallation of argon... |
15 P Isotopes of phosphorus Although phosphorus has 24 isotopes from 24P to 47P, only one of these isotopes is stable 31P; as such, it is considered a monoisotopic element. The longest-lived radioactive isotopes are 33P with a half-life of 25.34 days and 32P with a half-life of 14.263 days. All other have half-lives under... |
16 S Isotopes of sulfur Sulfur has 25 known isotopes with mass numbers ranging from 26 to 49, four of which are stable: 32S , 33S , 34S , and 36S... |
17 Cl Isotopes of chlorine Chlorine has 24 isotopes with mass numbers ranging from 28Cl to 51Cl and 2 isomers . There are two principal stable isotopes, 35Cl and 37Cl , found in the relative proportions of 37.89:12.11, not 3:1, respectively, giving chlorine a standard atomic mass of 35.453, not 35.5... |
18 Ar Isotopes of argon Argon has 24 known isotopes, from 30Ar to 53Ar and 1 isomer , three of which are stable, 36Ar, 38Ar, and 40Ar. On Earth, 40Ar makes up 99.6% of natural argon. The longest-lived radioactive isotopes are 39Ar with a half-life of 269 years, 42Ar with a half-life of 32.9 years, and 37Ar with a... |
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| 19 K Isotopes of potassium Potassium has 25 known isotopes from 32K to 56K. Three isotopes occur naturally: stable 39K and 41K , and the long-lived radioisotope 40K . The standard atomic mass is 39.0983 u. Naturally occurring 40K decays to stable 40Ar by electron capture or positron emission... |
20 Ca Isotopes of calcium Calcium has a total of 24 isotopes, from 34Ca to 57Ca. There are five observationally stable isotopes , plus one isotope with such a long half-life that for all practical purposes it can be considered stable... |
21 Sc Isotopes of scandium Naturally occurring scandium is composed of one stable isotope 45Sc. Twenty-four radioisotopes have been characterized with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours... |
22 Ti Isotopes of titanium Naturally occurring titanium is composed of 5 stable isotopes; 46Ti, 47Ti, 48Ti, 49Ti and 50Ti with 48Ti being the most abundant... |
23 V Isotopes of vanadium Naturally occurring vanadium is composed of one stable isotope 51V and one radioactive isotope 50V with a half-life of 1.5×1017 years. 24 artificial radioisotopes have been characterized with the most stable being 49V with a half-life of 330 days, and 48V with a half-life of 15.9735 days... |
24 Cr Isotopes of chromium Naturally occurring chromium is composed of four stable isotopes; 50Cr, 52Cr, 53Cr, and 54Cr with 52Cr being the most abundant . 50Cr is suspected of decaying by β+β+ to 50Ti with a half-life of 1.8x1017 years... |
25 Mn Isotopes of manganese Naturally occurring manganese is composed of 1 stable isotope; 55Mn. 25 radioisotopes have been characterized with the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days... |
26 Fe Isotopes of iron Naturally occurring iron consists of four isotopes: 5.845% of 54Fe , 91.754% of 56Fe, 2.119% of 57Fe and 0.282% of 58Fe. There are 24 known radioactive isotopes and their half-lives are shown below... |
27 Co Isotopes of cobalt Naturally occurring cobalt is composed of 1 stable isotope, 59Co. 28 radioisotopes have been characterized with the most stable being 60Co with a half-life of 5.2714 years, 57Co with a half-life of 271.79 days, 56Co with a half-life of 77.27 days, and 58Co with a half-life of 70.86 days... |
28 Ni Isotopes of nickel Naturally occurring nickel is composed of five stable isotopes; , , , and with being the most abundant . 58Ni may decay by double beta-plus decay to 58Fe. 26 radioisotopes have been characterised with the most stable being with a half-life of 76,000 years, with a half-life of 100.1 years,... |
29 Cu Isotopes of copper Copper has two stable isotopes, 63Cu and 65Cu, along with 27 radioisotopes. The most stable of these is 67Cu with a half-life of 61.83 hours. The least stable is 54Cu with a half-life of approximately 75 ns. Most have half-lives under a minute... |
30 Zn Isotopes of zinc Naturally occurring zinc is composed of the 5 stable isotopes 64Zn, 66Zn, 67Zn, 68Zn, and 70Zn with 64Zn being the most abundant . Twenty-five radioisotopes have been characterised with the most abundant and stable being 65Zn with a half-life of 244.26 days, and 72Zn with a half-life of 46.5 hours... |
31 Ga Isotopes of gallium Natural gallium consists of a mixture of two stable isotopes: gallium-69 and gallium-71. The most commercially important radioisotopes are gallium-67 and gallium-68.... |
32 Ge Isotopes of germanium Germanium has five naturally occurring isotopes, 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Of these, 76Ge is very slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 1021 years , giving it the distinction of being the nuclide with the longest directly measured... |
33 As Isotopes of arsenic Arsenic has 33 known isotopes and at least 10 isomers. Only one of these isotopes, 75As, is stable; as such, it is considered a monoisotopic element. The longest-lived radioisotope is 73As has a half-life of 80 days. Arsenic has been proposed as a "salting" material for nuclear weapons... |
34 Se Isotopes of selenium Selenium has six naturally occurring isotopes, five of which are stable: 74Se, 76Se, 77Se, 78Se, and 80Se. The last three also occur as fission products, along with 79Se which has a half-life of 327,000 years, and 82Se which has a very long half-life and for practical purposes can be considered... |
35 Br Isotopes of bromine Bromine has two stable isotopes and 30 known unstable isotopes, the most stable of which is 77Br with a half-life of 57.036 hoursStandard atomic mass: 79.904 u- Table :- Notes :... |
36 Kr Isotopes of krypton There are 33 known isotopes of krypton from 69 to 101. Naturally occurring krypton is made of six stable isotopes, two of which may be slightly radioactive. Its spectral signature can be produced with some very sharp lines. 81Kr, the product of atmospheric reactions is produced with the other... |
| 37 Rb Isotopes of rubidium Rubidium has 32 isotopes, with naturally occurring rubidium being composed of just two isotopes; 85Rb and the radioactive 87Rb . Normal mixes of rubidium are radioactive enough to fog photographic film in approximately 30 to 60 days. Standard atomic mass is 85.4678 u.87Rb has a half-life of... |
38 Sr Isotopes of strontium The alkaline earth metal strontium has four stable, naturally occurring isotopes:84Sr , 86Sr , 87Sr and 88Sr . It has a standard atomic mass of 87.62 u.... |
39 Y Isotopes of yttrium Natural yttrium is composed of only one isotope 89Y. The most stable radioisotopes are 88Y which has a half-life of 106.65 days and 91Y with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87Y, which has a half-life of 79.8 hours, and 90Y, with 64 hours... |
40 Zr Isotopes of zirconium Naturally occurring zirconium is composed of four stable isotopes , and one very long-lived radioisotope , a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×1019 years; it can also undergo single beta decay which is not yet observed, but the theoretically... |
41 Nb Isotopes of niobium Naturally occurring niobium , element 41, is composed of one stable isotope . 93Nb is the lightest nuclide theoretically susceptible to spontaneous fission, and although this has never been observed, it makes niobium theoretically the lightest element with no stable isotope... |
42 Mo Isotopes of molybdenum There are 33 known isotopes of molybdenum ranging in atomic mass from 83 to 115, as well as four metastable nuclear isomers. Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98, and 100. Of these naturally occurring isotopes, six have never been observed to decay, but all... |
43 Tc Isotopes of technetium Technetium is the first of the two elements in the first 82 that have no stable isotopes ; the other such element is promethium. It is primarily artificial, only trace quantities existing in nature produced by spontaneous fission or neutron capture by molybdenum... |
44 Ru Isotopes of ruthenium Naturally occurring ruthenium is composed of seven stable isotopes. Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are 106Ru with a half-life of 373.59 days, 103Ru with a half-life of 39.26 days and 97Ru with a half-life of 2.9 days.Twenty-four... |
45 Rh Isotopes of rhodium Naturally occurring rhodium is composed of only one stable isotope, 103Rh. The most stable radioisotopes are 101Rh with a half-life of 3.3 years, 102Rh with a half-life of 207 days, 102mRh with a half-life of 2.9 years, and 99Rh with a half-life of 16.1 days. Thirty other radioisotopes have been... |
46 Pd Isotopes of palladium Naturally occurring palladium is composed of six stable isotopes, 102Pd, 104Pd, 105Pd, 106Pd, 108Pd, and 110Pd. The most stable radioisotopes are 107Pd with a half-life of 6.5 million years, 103Pd with a half-life of 17 days, and 100Pd with a half-life of 3.63 days... |
47 Ag Isotopes of silver Naturally occurring silver is composed of the two stable isotopes 107Ag and 109Ag with 107Ag being the more abundant... |
48 Cd Isotopes of cadmium Naturally occurring cadmium is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decays were never observed, due to extremely long half-life times... |
49 In Isotopes of indium Indium consists of two primordial nuclides, with the most common nuclide being measurably radioactive . The stable isotope 113In is only 4.3% of naturally occurring indium... |
50 Sn Isotopes of tin Tin is the element with the greatest number of stable isotopes , which is probably related to the fact that 50 is a "magic number" of protons. 29 additional unstable isotopes are known, including the "doubly magic" tin-100 and tin-132 . The longest-lived radioisotope is 126Sn with a half-life... |
51 Sb Isotopes of antimony Antimony occurs in two stable isotopes, 121Sb and 123Sb. There are thirty-five artificial radioactive isotopes, the longest-lived of which are 125Sb with a half-life of 2.75856 years, 124Sb with a half-life of 60.2 days, and 126Sb with a half-life of 12.35 days... |
52 Te Isotopes of tellurium There are 38 known isotopes and 17 nuclear isomers of tellurium with atomic masses that range from 105 to 142. These are listed in the table below.Naturally occurring tellurium on Earth consists of eight isotopes... |
53 I Isotopes of iodine There are 37 known isotopes of iodine and only one, 127I, is stable. Iodine is thus a monoisotopic element.Its longest-lived radioactive isotope, 129I, has a half-life of 15.7 million years, which is far too short for it to exist as a primordial nuclide... |
54 Xe Isotopes of xenon Naturally occurring xenon is made of nine stable isotopes. Xenon has the second highest number of stable isotopes. Only tin, with 10 stable isotopes, has more... |
| 55 Cs Isotopes of caesium Caesium has 40 known isotopes. The atomic masses of these isotopes range from 112 to 151. Only one isotope, 133Cs, is stable. The longest-lived radioisotopes are 135Cs with a half-life of 2.3 million years, 137Cs with a half-life of 30.1671 years and 134Cs with a half-life of 2.0652 years... |
56 Ba Isotopes of barium Naturally occurring barium is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, recently identified as being unstable by geochemical means... |
* | 72 Hf Isotopes of hafnium Natural hafnium consists of five stable isotopes and one very long-lived radioisotope, 174Hf, with a half-life of 2×1015 years. In addition, there are 30 other known radionuclides, the most stable of which is 182Hf with a half-life of 8.9×106 years. No other radioisotope has a... |
73 Ta Isotopes of tantalum Natural tantalum consists of two stable isotopes: 181Ta and .The latter nuclide is predicted to decay in three ways: isomeric transition to the ground state of , beta decay to , and electron capture to . However, no radioactivity from any decay mode of this nuclear isomer has ever been observed... |
74 W Isotopes of tungsten Naturally occurring tungsten consists of four stable isotopes and one isotope, 180W, with an extremely long half-life of 1.8 ± 0.2 Ea... |
75 Re Isotopes of rhenium Naturally occurring rhenium is 37.4% 185Re, which is stable, and 62.6% 187Re, which is unstable but has a very long half-life... |
76 Os Isotopes of osmium Osmium has seven naturally occurring isotopes, 6 of which are stable: 184Os, 187Os, 188Os, 189Os, 190Os, and 192Os. The other one, 186Os, has an extremely long half-life and for practical purposes can be considered to be stable as well... |
77 Ir Isotopes of iridium There are two natural isotopes of iridium , and 34 radioisotopes, the most stable radioisotope being 192Ir with a half-life of 73.83 days, and many nuclear isomers, the most stable of which is 192m2Ir with a half-life of 241 years, all other isomers have half-lives under a year, most under a... |
78 Pt Isotopes of platinum Natural Platinum occurs in five stable isotopes and one very-long lived radioisotope . There are also 31 known artificial radioisotopes, the longest-lived of which is 193Pt with a half-life of 50 years... |
79 Au Isotopes of gold Gold has one stable isotope, 197Au, and 36 radioisotopes with 195Au being the most stable with a half-life of 186 days.Gold is currently considered the heaviest Monoisotopic element .Gold has been proposed as a material for creating a salted nuclear weapon Gold (Au) has one stable isotope, 197Au,... |
80 Hg Isotopes of mercury There are seven stable isotopes of mercury with 202Hg being the most abundant . The longest-lived radioisotopes are 194Hg with a half-life of 444 years, and 203Hg with a half-life of 46.612 days. Most of the remaining radioisotopes have half-lives that are less than a day... |
81 Tl Isotopes of thallium Thallium has 37 isotopes which have atomic masses that range from 176 to 212. 203Tl and 205Tl are the only stable isotopes and 204Tl is the most stable radioisotope with a half-life of 3.78 years... |
82 Pb Isotopes of lead Lead has four stable isotopes: 204Pb, 206Pb, 207Pb, 208Pb. Lead-204 is entirely a primordial nuclide and is not a radiogenic nuclide. The three isotopes lead-206, lead-207, and lead-208 represent the ends of three decay chains called the uranium series , the actinium series, and the thorium... |
83 Bi Isotopes of bismuth Bismuth has no stable isotopes, but does have one very long-lived isotope, thus the standard atomic mass can be given. Although bismuth-209 is now known to be unstable, it has classically been considered to be a "stable" isotope because it has a half-life of over 1.9×1019 years, which is... |
84 Po Isotopes of polonium Polonium has 42 isotopes, all of which are radioactive, with between 186 and 227 nucleons. 210Po with a half-life of 138.376 days has the longest half-life of naturally occurring polonium. 209Po with a half-life of 103 years has the longest half-life of all isotopes of polonium... |
85 At Isotopes of astatine Astatine has 37 known isotopes, all of which are radioactive; the range of their mass numbers is from 191 to 229. There exist also 23 metastable excited states... |
86 Rn Isotopes of radon There are 39 known isotopes of radon from 193Rn to 231Rn. The most stable isotope is 222Rn with a half-life of 3.823 days. Four isotopes, 218, 219, 220, 222Rn occur in trace quantities in nature as decay products of, respectively, 218At, 223Ra, 224Ra, and 226Ra... |
| 87 Fr Isotopes of francium Francium has no stable isotopes. A standard atomic mass cannot be given. Its most stable isotope is 223Fr with a half-life of 22 minutes, which is also the only naturally occurring isotope, occurring in trace quantities as an intermediate decay product of 235U.Of elements whose most stable... |
88 Ra Isotopes of radium Radium has no stable or nearly stable isotopes, and thus a standard atomic mass cannot be given. The longest lived, and most common, isotope of radium is 226Ra with a half-life of 1600 years... |
** | 104 Rf Isotopes of rutherfordium Rutherfordium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was either 259Rf in 1966 or 257Rf in 1969. There are 15 known radioisotopes from 253Rf to 268Rf and 4 isomers... |
105 Db Isotopes of dubnium Dubnium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 261Db in 1968. There are 12 known radioisotopes from 256Db to 270Db, and 1-3 isomers... |
106 Sg Isotopes of seaborgium Seaborgium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 263mSg in 1974. There are 12 known radioisotopes from 258Sg to 271Sg and 2 known isomers... |
107 Bh Isotopes of bohrium Bohrium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 262Bh in 1981. There are 12 known isotopes ranging from 260Bh to 275Bh, and 1 isomer, 262mBh... |
108 Hs Isotopes of hassium Hassium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 265Hs in 1984. There are 12 known isotopes from 263Hs to 277Hs and 1-4 isomers... |
109 Mt Isotopes of meitnerium Meitnerium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 266Mt in 1982 . There are seven known isotopes, from 266Mt to 278Mt... |
110 Ds Isotopes of darmstadtium Darmstadtium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 269Ds in 1994. There are 7 or 8 known radioisotopes from 267Ds to 281Ds and 2 or 3 known isomers... |
111 Rg Isotopes of roentgenium Roentgenium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 272Rg in 1994, which is also the only directly synthesized isotope, all others are decay products of ununtrium,... |
112 Cn |
113 Uut Isotopes of ununtrium Ununtrium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 284Uut as a decay product of 288Uup in 2003. The first isotope to be directly synthesized was 278Uut in 2004. There... |
114 Uuq Isotopes of ununquadium Ununquadium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 289Uuq in 1999 . Ununquadium has five confirmed isotopes, and possibly 2 nuclear isomers... |
115 Uup Isotopes of ununpentium Ununpentium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 288Uup in 2004. There are four known radioisotopes from 287Uup to 290Uup... |
116 Uuh Isotopes of ununhexium Ununhexium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 293Uuh in 2000. There are four known radioisotopes from 290Uuh to 293Uuh... |
117 Uus Isotopes of ununseptium Ununseptium is the most-recently synthesized artificial element, and much of the data is hypothetical. As any artificial element, a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotopes to be synthesized were 293Uus and 294Uus in 2009... |
118 Uuo Isotopes of ununoctium Ununoctium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 294Uuo in 2006. All data is hypothetical... |
| * | 57 La Isotopes of lanthanum Naturally occurring lanthanum is composed of one stable and one radioactive isotope, with the stable isotope, 139La, being the most abundant . 38 radioisotopes have been characterized with the most stable being 138La with a half-life of 102×109 years, 137La with a half-life of 60,000 years... |
58 Ce Isotopes of cerium Naturally occurring cerium is composed of 4 stable isotopes: 136Ce, 138Ce, 140Ce, and 142Ce with 140Ce being the most abundant ; 136Ce, 138Ce, and 142Ce are predicted to undergo double beta decay but this process has never been observed... |
59 Pr Isotopes of praseodymium Naturally occurring praseodymium is composed of one stable isotope, 141Pr. Thirty-eight radioisotopes have been characterized with the most stable being 143Pr with a half-life of 13.57 days and 142Pr with a half-life of 19.12 hours... |
60 Nd Isotopes of neodymium Naturally occurring neodymium is composed of 5 stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant , and 2 radioisotopes, 144Nd and 150Nd... |
61 Pm Isotopes of promethium Promethium has no stable isotopes, and does not exist in nature, except in trace quantities as a product of spontaneous fission. It is a synthetic element, first produced in 1945. Thirty-eight radioisotopes have been characterized, with the most stable being 145Pm with a half-life of 17.7 years,... |
62 Sm Isotopes of samarium Naturally occurring samarium is composed of five stable isotopes, 144Sm, 149Sm, 150Sm, 152Sm and 154Sm, and two extremely long-lived radioisotopes, 147Sm and 148Sm , with 152Sm being the most abundant... |
63 Eu Isotopes of europium Naturally occurring europium is composed of 2 isotopes, 151Eu and 153Eu, with 153Eu being the most abundant . While 153Eu is stable, 151Eu was recently found to be unstable and to undergo alpha decay with half-life of... |
64 Gd Isotopes of gadolinium Naturally occurring gadolinium is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant... |
65 Tb Isotopes of terbium Naturally occurring terbium is composed of 1 stable isotope, 159Tb. 36 radioisotopes have been characterized, with the most stable being 158Tb with a half-life of 180 years, 157Tb with a half-life of 71 years, and 160Tb with a half-life of 72.3 days... |
66 Dy Isotopes of dysprosium Naturally occurring dysprosium is composed of 7 stable isotopes, 156Dy, 158Dy, 160Dy, 161Dy, 162Dy, 163Dy and 164Dy, with 164Dy being the most abundant . 29 radioisotopes have been characterized, with the most stable being 154Dy with a half-life of 3.0 million years, 159Dy with a half-life of... |
67 Ho Isotopes of holmium Natural holmium contains one stable isotope, 165Ho. A number of synthetic radioactive isotopes are known, the most stable one is 163Ho, with a half-life of 4,570 years... |
68 Er Isotopes of erbium Naturally occurring erbium is composed of 6 stable isotopes, 162Er, 164Er, 166Er, 167Er, 168Er, and 170Er with 166Er being the most abundant... |
69 Tm Isotopes of thulium Naturally occurring thulium is composed of 1 stable isotope, 169Tm . 34 radioisotopes have been characterized, with the most stable being 171Tm with a half-life of 1.92 years, 170Tm with a half-life of 128.6 days, 168Tm with a half-life of 93.1 days, and 167Tm with a half-life of 9.25 days... |
70 Yb Isotopes of ytterbium Naturally occurring ytterbium is composed of 7 stable isotopes, 168Yb, 170Yb, 171Yb, 172Yb, 173Yb, 174Yb, and 176Yb, with 174Yb being the most abundant . 27 radioisotopes have been characterized, with the most stable being 169Yb with a half-life of 32.026 days, 175Yb with a half-life of 4.185... |
71 Lu Isotopes of lutetium Naturally occurring lutetium is composed of 1 stable isotope 175Lu and one long-lived radioisotope, 176Lu with a half-life of 3.78 × 1010 years . 34 radioisotopes have been characterized, with the most stable, besides 176Lu, being 174Lu with a half-life of 3.31 years, and 173Lu with a... |
| ** | 89 Ac Isotopes of actinium Actinium has no stable isotopes, thus a standard atomic mass cannot be given. There are 31 known isotopes, from 206Ac to 236Ac, and 2 isomers. Two isotopes are found in nature, 227Ac and 228Ac, as intermediate decay products of, respectively, 235U and 238U... |
90 Th Isotopes of thorium Although thorium has 6 naturally occurring isotopes, none of these isotopes are stable; however, one isotope, 232Th, is relatively stable, with a half-life of 14.05 billion years, considerably longer than the age of the earth, and even slightly longer than the generally-accepted age of the... |
91 Pa Isotopes of protactinium Protactinium has no stable isotopes. There are three naturally occurring isotopes, allowing a standard mass to be given.Standard atomic mass: 231.03588 u... |
92 U Isotopes of uranium Uranium is a naturally occurring radioactive element that has no stable isotopes but two primordial isotopes that have long half-life and are found in appreciable quantity in the Earth's crust, along with the decay product uranium-234. The average atomic mass of natural uranium is 238.02891 u... |
93 Np Isotopes of neptunium Neptunium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes... |
94 Pu Isotopes of plutonium Plutonium is an artificial element, except for trace quantities of primordial 244Pu, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. It was synthesized long before being found in nature, the first isotope synthesized being 238Pu in 1940.... |
95 Am Isotopes of americium Americium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 241Am in 1944.... |
96 Cm Isotopes of curium Curium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope synthesized was 242Cm in 1944.... |
97 Bk Isotopes of berkelium Berkelium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are 20 known radioisotopes, from 235Bk to 254Bk, and 6 nuclear isomers... |
98 Cf Isotopes of californium Californium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 245Cf in 1950. There are 20 known radioisotopes ranging from 237Cf to 256Cf and one nuclear isomer, 249mCf... |
99 Es Isotopes of einsteinium Einsteinium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered was 253Es in 1952... |
100 Fm Isotopes of fermium Fermium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered was 255Fm in 1952. 250Fm was independently synthesized shortly after the discovery of 255Fm... |
101 Md Isotopes of mendelevium Mendelevium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 256Md in 1955. There are 18 known radioisotopes, ranging in atomic mass from 245Md to 262Md, and 5 isomers... |
102 No Isotopes of nobelium Nobelium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 254No in 1966. There are 16 known radioisotopes which are 248No and 250No to 264No, and 3 isomers, 251mNo, 253mNo,... |
103 Lr Isotopes of lawrencium Lawrencium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 258Lr in 1961. There are eleven known radioisotopes from 252Lr to 262Lr, and 1 isomer . The longest-lived isotope... |