Chapter 15: Atomic Masses
- Page ID
- 46259
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| Atomic Number, Z | Name | Atomic Mass Number, A | Symbol | Atomic Mass (u) | Percent Abundance or Decay Mode | Half-life, t1/2 |
|---|---|---|---|---|---|---|
| 0 | neutron | 1 | \(n\) | 1.008 665 | \(\beta^{-}\) | 10.37 min |
| 1 | Hydrogen | 1 | \({ }^{1} \mathrm{H}\) | 1.007 825 | 99.985% | |
| Deuterium | 2 | \({ }^{2} \mathrm{H} \text { or } \mathrm{D}\) | 2.014 102 | 0.015% | ||
| Tritium | 3 | \({ }^{3} \mathrm{H} \text { or } \mathrm{T}\) | 3.016 050 | \(\beta^{-}\) | 12.33 y | |
| 2 | Helium | 3 | \({ }^{3} \mathrm{He}\) | 3.016 030 | \(1.38 \times 10^{-4} \%\) | |
| 4 | \({ }^{4} \mathrm{He}\) | 4.002 603 | \(\approx 100 \%\) | |||
| 3 | Lithium | 6 | \({ }^{6} \mathrm{Li}\) | 6.015 121 | 7.5% | |
| 7 | \({ }^{7} \mathrm{Li}\) | 7.016 003 | 92.5% | |||
| 4 | Beryllium | 7 | \({ }^{7} \mathrm{Be}\) | 7.016 928 | EC | 53.29 d |
| 9 | \({ }^{9} \mathrm{Be}\) | 9.012 182 | 100% | |||
| 5 | Boron | 10 | \({ }^{10} \mathrm{~B}\) | 10.012 937 | 19.9% | |
| 11 | \({ }^{11} \mathrm{~B}\) | 11.009 305 | 80.1% | |||
| 6 | Carbon | 11 | \({ }^{11} \mathrm{C}\) | 11.011 432 | EC, \(\beta^{+}\) | |
| 12 | \({ }^{12} \mathrm{C}\) | 12.000 000 | 98.90% | |||
| 13 | \({ }^{13} \mathrm{C}\) | 13.003 355 | 1.10% | |||
| 14 | \({ }^{14} \mathrm{C}\) | 14.003 241 | \(\beta^{-}\) | 5730 y | ||
| 7 | Nitrogen | 13 | \({ }^{13} \mathrm{~N}\) | 13.005 738 | \(\beta^{+}\) | 9.96 min |
| 14 | \({ }^{14} \mathrm{~N}\) | 14.003 074 | 99.63% | |||
| 15 | \({ }^{15} \mathrm{~N}\) | 15.000 108 | 0.37% | |||
| 8 | Oxygen | 15 | \({ }^{15} \mathrm{O}\) | 15.003 065 | EC, \(\beta^{+}\) | 122 s |
| 16 | \({ }^{16} \mathrm{O}\) | 15.994 915 | 99.76% | |||
| 18 | \({ }^{18} \mathrm{O}\) | 17.999 160 | 0.200% | |||
| 9 | Fluorine | 18 | \({ }^{18} \mathrm{~F}\) | 18.000 937 | EC, \(\beta^{+}\) | 1.83 h |
| 19 | \({ }^{19} \mathrm{~F}\) | 18.998 403 | 100% | |||
| 10 | Neon | 20 | \({ }^{20} \mathrm{Ne}\) | 19.992 435 | 90.51% | |
| 22 | \({ }^{22} \mathrm{Ne}\) | 21.991 383 | 9.22% | |||
| 11 | Sodium | 22 | \({ }^{22} \mathrm{Na}\) | 21.994 434 | \(\beta^{+}\) | 2.602 y |
| 23 | \({ }^{23} \mathrm{Na}\) | 22.989 767 | 100% | |||
| 24 | \({ }^{24} \mathrm{Na}\) | 23.990 961 | \(\beta^{-}\) | 14.96 h | ||
| 12 | Magnesium | 24 | \({ }^{24} \mathrm{Mg}\) | 23.985 042 | 78.99% | |
| 13 | Aluminum | 27 | \({ }^{27} \mathrm{Al}\) | 26.981 539 | 100% | |
| 14 | Silicon | 28 | \({ }^{28} \mathrm{Si}\) | 27.976 927 | 92.23% | 2.62h |
| 31 | \({ }^{31} \mathrm{Si}\) | 30.975 362 | \(\beta^{-}\) | |||
| 15 | Phosphorus | 31 | \({ }^{31} \mathrm{P}\) | 30.973 762 | 100% | |
| 32 | \({ }^{32} \mathrm{P}\) | 31.973 907 | \(\beta^{-}\) | 14.28 d | ||
| 16 | Sulfur | 32 | \(32 \mathrm{S}\) | 31.972 070 | 95.02% | |
| 35 | \({ }^{35} \mathrm{S}\) | 34.969 031 | \(\beta^{-}\) | 87.4 d | ||
| 17 | Chlorine | 35 | \({ }^{35} \mathrm{Cl}\) | 34.968 852 | 75.77% | |
| 37 | \({ }^{37} \mathrm{Cl}\) | 36.965 903 | 24.23% | |||
| 18 | Argon | 40 | \({ }^{40} \mathrm{Ar}\) | 39.962 384 | 99.60% | |
| 19 | Potassium | 39 | \({ }^{39} \mathrm{~K}\) | 38.963 707 | 93.26% | |
| 40 | \({ }^{40} \mathrm{~K}\) | 39.963 999 | 0.0117%, EC, \(\beta^{-}\) | \(1.28 \times 10^{9} \mathrm{y}\) | ||
| 20 | Calcium | 40 | \({ }^{40} \mathrm{Ca}\) | 39.962 591 | 96.94% | |
| 21 | Scandium | 45 | \({ }^{45} \mathrm{Sc}\) | 44.955 910 | 100% | |
| 22 | Titanium | 48 | \({ }^{48} \mathrm{Ti}\) | 47.947 947 | 73.8% | |
| 23 | Vanadium | 51 | \({ }^{51} \mathrm{~V}\) | 50.943 962 | 99.75% | |
| 24 | Chromium | 52 | \({ }^{52} \mathrm{Cr}\) | 51.940 509 | 83.79% | |
| 25 | Manganese | 55 | \({ }^{55} \mathrm{Mn}\) | 54.938 047 | 100% | |
| 26 | Iron | 56 | \({ }^{56} \mathrm{Fe}\) | 55.934 939 | 91.72% | |
| 27 | Cobalt | 59 | \({ }^{59} \mathrm{Co}\) | 58.933 198 | 100% | |
| 60 | \({ }^{60} \mathrm{Co}\) | 59.933 819 | \(\beta^{-}\) | 5.271 y | ||
| 28 | Nickel | 58 | \({ }^{58} \mathrm{Ni}\) | 57.935 346 | 68.27% | |
| 60 | \(60 \mathrm{Ni}\) | 59.930 788 | 26.10% | |||
| 29 | Copper | 63 | \({ }^{63} \mathrm{Cu}\) | 62.939 598 | 69.17% | |
| 65 | \({ }^{65} \mathrm{Cu}\) | 64.927 793 | 30.83% | |||
| 30 | Zinc | 64 | \({ }^{64} \mathrm{Zn}\) | 63.929 145 | 48.6% | |
| 66 | \({ }^{66} \mathrm{Zn}\) | 65.926 034 | 27.9% | |||
| 31 | Gallium | 69 | \({ }^{69} \mathrm{Ga}\) | 68.925 580 | 60.1% | |
| 32 | Germanium | 72 | \({ }^{72} \mathrm{Ge}\) | 71.922 079 | 27.4% | |
| 74 | \({ }^{74} \mathrm{Ge}\) | 73.921 177 | 36.5% | |||
| 33 | Arsenic | 75 | \({ }^{75} \mathrm{As}\) | 74.921 594 | 100% | |
| 34 | Selenium | 80 | \({ }^{80} \mathrm{Se}\) | 79.916 520 | 49.7% | |
| 35 | Bromine | 79 | \({ }^{79} \mathrm{Br}\) | 78.918 336 | 50.69% | |
| 36 | Krypton | 84 | \({ }^{84} \mathrm{Kr}\) | 83.911 507 | 57.0% | |
| 37 | Rubidium | 85 | \({ }^{85} \mathrm{Rb}\) | 84.911 794 | 72.17% | |
| 38 | Strontium | 86 | \({ }^{86} \mathrm{Sr}\) | 85.909 267 | 9.86% | |
| 88 | \({ }^{88} \mathrm{Sr}\) | 87.905 619 | 82.58% | |||
| 90 | \({ }^{90} \mathrm{Sr}\) | 89.907 738 | \(\beta^{-}\) | 28.8 y | ||
| 39 | Yttrium | 89 | \({ }^{89} \mathrm{Y}\) | 88.905 849 | 100% | |
| 90 | \({ }^{90} \mathrm{Y}\) | 89.907 152 | \(\beta^{-}\) | 64.1 h | ||
| 40 | Zirconium | 90 | \({ }^{90} \mathrm{Zr}\) | 89.904 703 | 51.45% | |
| 41 | Niobium | 93 | \({ }^{93} \mathrm{Nb}\) | 92.906 377 | 100% | |
| 42 | Molybdenum | 98 | \({ }^{98} \mathrm{Mo}\) | 97.905 406 | 24.13% | |
| 43 | Technetium | 98 | \({ }^{98} \mathrm{Tc}\) | 97.907 215 | \(\beta^{-}\) | \(4.2 \times 10^{6} \mathrm{y}\) |
| 44 | Ruthenium | 102 | \({ }^{102} \mathrm{Ru}\) | 101.904 348 | 31.6% | |
| 45 | Rhodium | 103 | \({ }^{103} \mathrm{Rh}\) | 102.905 500 | 100% | |
| 46 | Palladium | 106 | \({ }^{106} \mathrm{Pd}\) | 105.903 478 | 27.33% | |
| 47 | Silver | 107 | \({ }^{107} \mathrm{Ag}\) | 106.905 092 | 51.84% | |
| 109 | \({ }^{109} \mathrm{Ag}\) | 108.904 757 | 48.16% | |||
| 48 | Cadmium | 114 | \({ }^{114} \mathrm{Cd}\) | 113.903 357 | 28.73% | |
| 49 | Indium | 115 | \({ }^{115} \mathrm{In}\) | 114.903 880 | 95.7%, \(\beta^{-}\) | \(4.4 \times 10^{14} \mathrm{y}\) |
| 50 | Tin | 120 | \({ }^{120} \mathrm{Sn}\) | 119.902 200 | 32.59% | |
| 51 | Antimony | 121 | \({ }^{121} \mathrm{Sb}\) | 120.903 821 | 57.3% | |
| 52 | Tellurium | 130 | \({ }^{130} \mathrm{Te}\) | 129.906 229 | 33.8%, \(\beta^{-}\) | \(2.5 \times 10^{21} \mathrm{y}\) |
| 53 | Iodine | 127 | \({ }^{127} \mathrm{I}\) | 126.904 473 | 100% | |
| 131 | \({ }^{131} \mathrm{I}\) | 130.906 114 | \(\beta^{-}\) | 8.040 d | ||
| 54 | Xenon | 132 | \({ }^{132} \mathrm{Xe}\) | 131.904 144 | 26.9% | |
| 136 | \({ }^{136} \mathrm{Xe}\) | 135.907 214 | 8.9% | |||
| 55 | Cesium | 133 | \({ }^{133} \mathrm{Cs}\) | 132.905 429 | 100% | |
| 134 | \({ }^{134} \mathrm{Cs}\) | 133.906 696 | EC, \(\beta^{-}\) | 2.06 y | ||
| 56 | Barium | 137 | \({ }^{137} \mathrm{Ba}\) | 136.905 812 | 11.23% | |
| 138 | \({ }^{138} \mathrm{Ba}\) | 137.905 232 | 71.70% | |||
| 57 | Lanthanum | 139 | \({ }^{139} \mathrm{La}\) | 138.906 346 | 99.91% | |
| 58 | Cerium | 140 | \({ }^{140} \mathrm{Ce}\) | 139.905 433 | 88.48% | |
| 59 | Praseodymium | 141 | \({ }^{141} \mathrm{Pr}\) | 140.907 647 | 100% | |
| 60 | Neodymium | 142 | \({ }^{142} \mathrm{Nd}\) | 141.907 719 | 27.13% | |
| 61 | Promethium | 145 | \({ }^{145} \mathrm{Pm}\) | 144.912 743 | EC, \(\alpha\) | 17.7 y |
| 62 | Samarium | 152 | \({ }^{152} \mathrm{Sm}\) | 151.919 729 | 26.7% | |
| 63 | Europium | 153 | \({ }^{153} \mathrm{Eu}\) | 152.921 225 | 52.2% | |
| 64 | Gadolinium | 158 | \({ }^{158} \mathrm{Gd}\) | 157.924 099 | 24.84% | |
| 65 | Terbium | 159 | \({ }^{159} \mathrm{Tb}\) | 158.925 342 | 100% | |
| 66 | Dysprosium | 164 | \({ }^{164} \mathrm{Dy}\) | 163.929 171 | 28.2% | |
| 67 | Holmium | 165 | \({ }^{165} \mathrm{Ho}\) | 164.930 319 | 100% | |
| 68 | Erbium | 166 | \({ }^{166} \mathrm{Er}\) | 165.930 290 | 33.6% | |
| 69 | Thulium | 169 | \({ }^{169} \mathrm{Tm}\) | 168.934 212 | 100% | |
| 70 | Ytterbium | 174 | \({ }^{174} \mathrm{Yb}\) | 173.938 859 | 31.8% | |
| 71 | Lutecium | 175 | \({ }^{175} \mathrm{Lu}\) | 174.940 770 | 97.41% | |
| 72 | Hafnium | 180 | \({ }^{180} \mathrm{Hf}\) | 179.946 545 | 35.10% | |
| 73 | Tantalum | 181 | \({ }^{181} \mathrm{Ta}\) | 180.947 992 | 99.98% | |
| 74 | Tungsten | 184 | \({ }^{184} \mathrm{W}\) | 183.950 928 | 30.67% | |
| 75 | Rhenium | 187 | \({ }^{187} \mathrm{Re}\) | 186.955 744 | 62.6%, \(\beta^{-}\) | \(4.6 \times 10^{10} \mathrm{y}\) |
| 76 | Osmium | 191 | \({ }^{191} \mathrm{Os}\) | 190.960 920 | \(\beta^{-}\) | 15.4 d |
| 192 | \({ }^{192} \mathrm{Os}\) | 191.961 467 | 41.0% | |||
| 77 | Iridium | 191 | \({ }^{191} \mathrm{Ir}\) | 190.960 584 | 37.3% | |
| 193 | \({ }^{193} \mathrm{Ir}\) | 192.962 917 | 62.7% | |||
| 78 | Platinum | 195 | \({ }^{195} \mathrm{Pt}\) | 194.964 766 | 33.8% | |
| 79 | Gold | 197 | \({ }^{197} \mathrm{Au}\) | 196.966 543 | 100% | |
| 198 | \({ }^{198} \mathrm{Au}\) | 197.968 217 | \(\beta^{-}\) | 2.696 d | ||
| 80 | Mercury | 199 | \({ }^{199} \mathrm{Hg}\) | 198.968 253 | 16.87% | |
| 202 | \({ }^{202} \mathrm{Hg}\) | 201.970 617 | 29.86% | |||
| 81 | Thallium | 205 | \({ }^{205} \mathrm{Tl}\) | 204.974 401 | 70.48% | |
| 82 | Lead | 206 | \({ }^{206} \mathrm{Pb}\) | 205.974 440 | 24.1% | |
| 207 | \({ }^{207} \mathrm{Pb}\) | 206.975 872 | 22.1% | |||
| 208 | \({ }^{208} \mathrm{Pb}\) | 207.976 627 | 52.4% | |||
| 210 | \({ }^{210} \mathrm{Pb}\) | 209.984 163 | \(\alpha, \beta^{-}\) | 22.3 y | ||
| 211 | \({ }^{211} \mathrm{Pb}\) | 210.988 735 | \(\beta^{-}\) | 36.1 min | ||
| 212 | \({ }^{212} \mathrm{Pb}\) | 211.991 871 | \(\beta^{-}\) | 10.64 h | ||
| 83 | Bismuth | 209 | \({ }^{209} \mathrm{Bi}\) | 208.980 374 | 100% | |
| 211 | \({ }^{211} \mathrm{Bi}\) | 210.987 255 | \(\alpha, \beta^{-}\) | 2.14 min | ||
| 84 | Polonium | 210 | \({ }^{210} \mathrm{Po}\) | 209.982 848 | \(\alpha\) | 138.38 d |
| 85 | Astatine | 218 | \({ }^{218} \mathrm{At}\) | 218.008 684 | \(\alpha, \beta^{-}\) | 1.6 s |
| 86 | Radon | 222 | \({ }^{222} \mathrm{Rn}\) | 222.017 570 | \(\alpha\) | 3.82 d |
| 87 | Francium | 223 | \({ }^{223} \mathrm{Fr}\) | 223.019 733 | \(\alpha, \beta^{-}\) | 21.8 min |
| 88 | Radium | 226 | \({ }^{226} \mathrm{Ra}\) | 226.025 402 | \(\alpha\) | \(1.60 \times 10^{3} \mathrm{y}\) |
| 89 | Actinium | 227 | \({ }^{227} \mathrm{Ac}\) | 227.027 750 | \(\alpha, \beta^{-}\) | 21.8 y |
| 90 | Thorium | 228 | \({ }^{228} \mathrm{Th}\) | 228.028 715 | \(\alpha\) | 1.91 y |
| 232 | \({ }^{232} \mathrm{Th}\) | 232.038 054 | 100%, \(\alpha\) | \(1.41 \times 10^{10} \mathrm{y}\) | ||
| 91 | Protactinium | 231 | \({ }^{231} \mathrm{~Pa}\) | 231.035 880 | \(\alpha\) | \(3.28 \times 10^{4} \mathrm{y}\) |
| 92 | Uranium | 233 | \({ }^{233} \mathrm{U}\) | 233.039 628 | \(\alpha\) | \(1.59 \times 10^{3} \mathrm{y}\) |
| 235 | \({ }^{235} \mathrm{U}\) | 235.043 924 | 0.720%, \(\alpha\) | \(7.04 \times 10^{8} \mathrm{y}\) | ||
| 236 | \({ }^{236} \mathrm{U}\) | 236.045 562 | \(\alpha\) | \(2.34 \times 10^{7} \mathrm{y}\) | ||
| 238 | \({ }^{238} \mathrm{U}\) | 238.050 784 | 99.2745%, \(\alpha\) | \(4.47 \times 10^{9} \mathrm{y}\) | ||
| 239 | \({ }^{239} \mathrm{U}\) | 239.054 289 | \(\beta^{-}\) | 23.5 min | ||
| 93 | Neptunium | 239 | \({ }^{239} \mathrm{Np}\) | 239.052 933 | \(\beta^{-}\) | 2.355 d |
| 94 | Plutonium | 239 | \({ }^{239} \mathrm{Pu}\) | 239.052 157 | \(\alpha\) | \(2.41 \times 10^{4} \mathrm{y}\) |
| 95 | Americium | 243 | \({ }^{243} \mathrm{Am}\) | 243.061 375 | \(\alpha\), fission | \(7.37 \times 10^{3} \mathrm{y}\) |
| 96 | Curium | 245 | \({ }^{245} \mathrm{Cm}\) | 245.065 483 | \(\alpha\) | \(8.50 \times 10^{3} \mathrm{y}\) |
| 97 | Berkelium | 247 | \({ }^{247} \mathrm{Bk}\) | 247.070 300 | \(\alpha\) | \(1.38 \times 10^{3} \mathrm{y}\) |
| 98 | Californium | 249 | \({ }^{249} \mathrm{Cf}\) | 249.074 844 | \(\alpha\) | 351 y |
| 99 | Einsteinium | 254 | \({ }^{254} \mathrm{Es}\) | 254.088 019 | \(\alpha, \beta^{-}\) | 276 d |
| 100 | Fermium | 253 | \({ }^{253} \mathrm{Fm}\) | 253.085 173 | EC, \(\alpha\) | 3.00 d |
| 101 | Mendelevium | 255 | \({ }^{255} \mathrm{Md}\) | 255.091 081 | EC, \(\alpha\) | 27 min |
| 102 | Nobelium | 255 | \({ }^{255} \mathrm{No}\) | 255.093 260 | EC, \(\alpha\) | 3.1 min |
| 103 | Lawrencium | 257 | \({ }^{257} \mathrm{Lr}\) | 257.099 480 | EC, \(\alpha\) | 0.646 s |
| 104 | Rutherfordium | 261 | \({ }^{261} \mathrm{Rf}\) | 261.108 690 | \(\alpha\) | 1.08 min |
| 105 | Dubnium | 262 | \({ }^{262} \mathrm{Db}\) | 262.113 760 | \(\alpha\), fission | 34 s |
| 106 | Seaborgium | 263 | \({ }^{263} \mathrm{Sg}\) | 263.11 86 | \(\alpha\), fission | 0.8 s |
| 107 | Bohrium | 262 | \({ }^{262} \mathrm{Bh}\) | 262.123 1 | \(\alpha\) | 0.102 s |
| 108 | Hassium | 264 | \({ }^{264} \mathrm{Hs}\) | 264.128 5 | \(\alpha\) | 0.08 ms |
| 109 | Meitnerium | 266 | \({ }^{266} \mathrm{Mt}\) | 266.137 8 | \(\alpha\) | 3.4 ms |