Atomic Masses

Atomic Masses
Atomic Number, Z Name Atomic Mass Number, A Symbol Atomic Mass (u) Percent Abundance or Decay Mode Half-life, t1/2
0 neutron 1 [latex]n[/latex] 1.008 665 [latex]{\beta }^{-}[/latex] 10.37 min
1 Hydrogen 1 [latex]{\text{}}^{1}\text{H}[/latex] 1.007 825 99.985%
Deuterium 2 [latex]{\text{}}^{2}\text{H or D}[/latex] 2.014 102 0.015%
Tritium 3 [latex]{\text{}}^{3}\text{H or T}[/latex] 3.016 050 [latex]{\beta }^{-}[/latex] 12.33 y
2 Helium 3 [latex]{\text{}}^{3}\text{He}[/latex] 3.016 030 [latex]1\text{.}\text{38}×{\text{10}}^{-4}\text{}\text{%}[/latex]
4 [latex]{\text{}}^{4}\text{He}[/latex] 4.002 603 [latex]\text{≈100%}\text{}[/latex]
3 Lithium 6 [latex]{\text{}}^{6}\text{Li}[/latex] 6.015 121 7.5%
7 [latex]{\text{}}^{7}\text{Li}[/latex] 7.016 003 92.5%
4 Beryllium 7 [latex]{\text{}}^{7}\text{Be}[/latex] 7.016 928 EC 53.29 d
9 [latex]{\text{}}^{9}\text{Be}[/latex] 9.012 182 100%
5 Boron 10 [latex]{\text{}}^{10}\text{B}[/latex] 10.012 937 19.9%
11 [latex]{\text{}}^{11}\text{B}[/latex] 11.009 305 80.1%
6 Carbon 11 [latex]{\text{}}^{11}\text{C}[/latex] 11.011 432 EC, [latex]{\beta }^{+}[/latex]
12 [latex]{\text{}}^{12}\text{C}[/latex] 12.000 000 98.90%
13 [latex]{\text{}}^{13}\text{C}[/latex] 13.003 355 1.10%
14 [latex]{\text{}}^{14}\text{C}[/latex] 14.003 241 [latex]{\beta }^{-}[/latex] 5730 y
7 Nitrogen 13 [latex]{\text{}}^{13}\text{N}[/latex] 13.005 738 [latex]{\beta }^{+}[/latex] 9.96 min
14 [latex]{\text{}}^{14}\text{N}[/latex] 14.003 074 99.63%
15 [latex]{\text{}}^{15}\text{N}[/latex] 15.000 108 0.37%
8 Oxygen 15 [latex]{\text{}}^{15}\text{O}[/latex] 15.003 065 EC, [latex]{\beta }^{+}[/latex] 122 s
16 [latex]{\text{}}^{16}\text{O}[/latex] 15.994 915 99.76%
18 [latex]{\text{}}^{18}\text{O}[/latex] 17.999 160 0.200%
9 Fluorine 18 [latex]{\text{}}^{18}\text{F}[/latex] 18.000 937 EC, [latex]{\beta }^{+}[/latex] 1.83 h
19 [latex]{\text{}}^{19}\text{F}[/latex] 18.998 403 100%
10 Neon 20 [latex]{\text{}}^{20}\text{Ne}[/latex] 19.992 435 90.51%
22 [latex]{\text{}}^{22}\text{Ne}[/latex] 21.991 383 9.22%
11 Sodium 22 [latex]{\text{}}^{22}\text{Na}[/latex] 21.994 434 [latex]{\beta }^{+}[/latex] 2.602 y
23 [latex]{\text{}}^{23}\text{Na}[/latex] 22.989 767 100%
24 [latex]{\text{}}^{24}\text{Na}[/latex] 23.990 961 [latex]{\beta }^{-}[/latex] 14.96 h
12 Magnesium 24 [latex]{\text{}}^{24}\text{Mg}[/latex] 23.985 042 78.99%
13 Aluminum 27 [latex]{\text{}}^{27}\text{Al}[/latex] 26.981 539 100%
14 Silicon 28 [latex]{\text{}}^{28}\text{Si}[/latex] 27.976 927 92.23% 2.62h
31 [latex]{\text{}}^{31}\text{Si}[/latex] 30.975 362 [latex]{\beta }^{-}[/latex]
15 Phosphorus 31 [latex]{\text{}}^{31}\text{P}[/latex] 30.973 762 100%
32 [latex]{\text{}}^{32}\text{P}[/latex] 31.973 907 [latex]{\beta }^{-}[/latex] 14.28 d
16 Sulfur 32 [latex]{\text{}}^{32}\text{S}[/latex] 31.972 070 95.02%
35 [latex]{\text{}}^{35}\text{S}[/latex] 34.969 031 [latex]{\beta }^{-}[/latex] 87.4 d
17 Chlorine 35 [latex]{\text{}}^{35}\text{Cl}[/latex] 34.968 852 75.77%
37 [latex]{\text{}}^{37}\text{Cl}[/latex] 36.965 903 24.23%
18 Argon 40 [latex]{\text{}}^{40}\text{Ar}[/latex] 39.962 384 99.60%
19 Potassium 39 [latex]{\text{}}^{39}\text{K}[/latex] 38.963 707 93.26%
40 [latex]{\text{}}^{40}\text{K}[/latex] 39.963 999 0.0117%, EC, [latex]{\beta }^{-}[/latex] [latex]1\text{.}\text{28}×{\text{10}}^{9}\text{y}[/latex]
20 Calcium 40 [latex]{\text{}}^{40}\text{Ca}[/latex] 39.962 591 96.94%
21 Scandium 45 [latex]{\text{}}^{45}\text{Sc}[/latex] 44.955 910 100%
22 Titanium 48 [latex]{\text{}}^{48}\text{Ti}[/latex] 47.947 947 73.8%
23 Vanadium 51 [latex]{\text{}}^{51}\text{V}[/latex] 50.943 962 99.75%
24 Chromium 52 [latex]{\text{}}^{52}\text{Cr}[/latex] 51.940 509 83.79%
25 Manganese 55 [latex]{\text{}}^{55}\text{Mn}[/latex] 54.938 047 100%
26 Iron 56 [latex]{\text{}}^{56}\text{Fe}[/latex] 55.934 939 91.72%
27 Cobalt 59 [latex]{\text{}}^{59}\text{Co}[/latex] 58.933 198 100%
60 [latex]{\text{}}^{60}\text{Co}[/latex] 59.933 819 [latex]{\beta }^{-}[/latex] 5.271 y
28 Nickel 58 [latex]{\text{}}^{58}\text{Ni}[/latex] 57.935 346 68.27%
60 [latex]{\text{}}^{60}\text{Ni}[/latex] 59.930 788 26.10%
29 Copper 63 [latex]{\text{}}^{63}\text{Cu}[/latex] 62.939 598 69.17%
65 [latex]{\text{}}^{65}\text{Cu}[/latex] 64.927 793 30.83%
30 Zinc 64 [latex]{\text{}}^{64}\text{Zn}[/latex] 63.929 145 48.6%
66 [latex]{\text{}}^{66}\text{Zn}[/latex] 65.926 034 27.9%
31 Gallium 69 [latex]{\text{}}^{69}\text{Ga}[/latex] 68.925 580 60.1%
32 Germanium 72 [latex]{\text{}}^{72}\text{Ge}[/latex] 71.922 079 27.4%
74 [latex]{\text{}}^{74}\text{Ge}[/latex] 73.921 177 36.5%
33 Arsenic 75 [latex]{\text{}}^{75}\text{As}[/latex] 74.921 594 100%
34 Selenium 80 [latex]{\text{}}^{80}\text{Se}[/latex] 79.916 520 49.7%
35 Bromine 79 [latex]{\text{}}^{79}\text{Br}[/latex] 78.918 336 50.69%
36 Krypton 84 [latex]{\text{}}^{84}\text{Kr}[/latex] 83.911 507 57.0%
37 Rubidium 85 [latex]{\text{}}^{85}\text{Rb}[/latex] 84.911 794 72.17%
38 Strontium 86 [latex]{\text{}}^{86}\text{Sr}[/latex] 85.909 267 9.86%
88 [latex]{\text{}}^{88}\text{Sr}[/latex] 87.905 619 82.58%
90 [latex]{\text{}}^{90}\text{Sr}[/latex] 89.907 738 [latex]{\beta }^{-}[/latex] ­ 28.8 y
39 Yttrium 89 [latex]{\text{}}^{89}\text{Y}[/latex] 88.905 849 100%
90 [latex]{\text{}}^{90}\text{Y}[/latex] 89.907 152 [latex]{\beta }^{-}[/latex] ­ 64.1 h
40 Zirconium 90 [latex]{\text{}}^{90}\text{Zr}[/latex] 89.904 703 51.45%
41 Niobium 93 [latex]{\text{}}^{93}\text{Nb}[/latex] 92.906 377 100%
42 Molybdenum 98 [latex]{\text{}}^{98}\text{Mo}[/latex] 97.905 406 24.13%
43 Technetium 98 [latex]{\text{}}^{98}\text{Tc}[/latex] 97.907 215 [latex]{\beta }^{-}[/latex] ­ [latex]4\text{.}2×{\text{10}}^{6}\text{y}[/latex]
44 Ruthenium 102 [latex]{\text{}}^{102}\text{Ru}[/latex] 101.904 348 31.6%
45 Rhodium 103 [latex]{\text{}}^{103}\text{Rh}[/latex] 102.905 500 100%
46 Palladium 106 [latex]{\text{}}^{106}\text{Pd}[/latex] 105.903 478 27.33%
47 Silver 107 [latex]{\text{}}^{107}\text{Ag}[/latex] 106.905 092 51.84%
109 [latex]{\text{}}^{109}\text{Ag}[/latex] 108.904 757 48.16%
48 Cadmium 114 [latex]{\text{}}^{114}\text{Cd}[/latex] 113.903 357 28.73%
49 Indium 115 [latex]{\text{}}^{115}\text{In}[/latex] 114.903 880 95.7%, [latex]{\beta }^{-}[/latex] ­ [latex]4\text{.}4×{\text{10}}^{\text{14}}\text{y}[/latex]
50 Tin 120 [latex]{\text{}}^{120}\text{Sn}[/latex] 119.902 200 32.59%
51 Antimony 121 [latex]{\text{}}^{121}\text{Sb}[/latex] 120.903 821 57.3%
52 Tellurium 130 [latex]{\text{}}^{130}\text{Te}[/latex] 129.906 229 33.8%, [latex]{\beta }^{-}[/latex] ­ [latex]2\text{.}5×{\text{10}}^{\text{21}}\text{y}[/latex]
53 Iodine 127 [latex]{\text{}}^{127}\text{I}[/latex] 126.904 473 100%
131 [latex]{\text{}}^{131}\text{I}[/latex] 130.906 114 [latex]{\beta }^{-}[/latex] ­ 8.040 d
54 Xenon 132 [latex]{\text{}}^{132}\text{Xe}[/latex] 131.904 144 26.9%
136 [latex]{\text{}}^{136}\text{Xe}[/latex] 135.907 214 8.9%
55 Cesium 133 [latex]{\text{}}^{133}\text{Cs}[/latex] 132.905 429 100%
134 [latex]{\text{}}^{134}\text{Cs}[/latex] 133.906 696 EC, [latex]{\beta }^{-}[/latex] ­ 2.06 y
56 Barium 137 [latex]{\text{}}^{137}\text{Ba}[/latex] 136.905 812 11.23%
138 [latex]{\text{}}^{138}\text{Ba}[/latex] 137.905 232 71.70%
57 Lanthanum 139 [latex]{\text{}}^{139}\text{La}[/latex] 138.906 346 99.91%
58 Cerium 140 [latex]{\text{}}^{140}\text{Ce}[/latex] 139.905 433 88.48%
59 Praseodymium 141 [latex]{\text{}}^{141}\text{Pr}[/latex] 140.907 647 100%
60 Neodymium 142 [latex]{\text{}}^{142}\text{Nd}[/latex] 141.907 719 27.13%
61 Promethium 145 [latex]{\text{}}^{145}\text{Pm}[/latex] 144.912 743 EC, [latex]\alpha[/latex] 17.7 y
62 Samarium 152 [latex]{\text{}}^{152}\text{Sm}[/latex] 151.919 729 26.7%
63 Europium 153 [latex]{\text{}}^{153}\text{Eu}[/latex] 152.921 225 52.2%
64 Gadolinium 158 [latex]{\text{}}^{158}\text{Gd}[/latex] 157.924 099 24.84%
65 Terbium 159 [latex]{\text{}}^{159}\text{Tb}[/latex] 158.925 342 100%
66 Dysprosium 164 [latex]{\text{}}^{164}\text{Dy}[/latex] 163.929 171 28.2%
67 Holmium 165 [latex]{\text{}}^{165}\text{Ho}[/latex] 164.930 319 100%
68 Erbium 166 [latex]{\text{}}^{166}\text{Er}[/latex] 165.930 290 33.6%
69 Thulium 169 [latex]{\text{}}^{169}\text{Tm}[/latex] 168.934 212 100%
70 Ytterbium 174 [latex]{\text{}}^{174}\text{Yb}[/latex] 173.938 859 31.8%
71 Lutecium 175 [latex]{\text{}}^{175}\text{Lu}[/latex] 174.940 770 97.41%
72 Hafnium 180 [latex]{\text{}}^{180}\text{Hf}[/latex] 179.946 545 35.10%
73 Tantalum 181 [latex]{\text{}}^{181}\text{Ta}[/latex] 180.947 992 99.98%
74 Tungsten 184 [latex]{\text{}}^{184}\text{W}[/latex] 183.950 928 30.67%
75 Rhenium 187 [latex]{\text{}}^{187}\text{Re}[/latex] 186.955 744 62.6%, [latex]{\beta }^{-}[/latex] [latex]4\text{.}6×{\text{10}}^{\text{10}}\text{y}[/latex]
76 Osmium 191 [latex]{\text{}}^{191}\text{Os}[/latex] 190.960 920 [latex]{\beta }^{-}[/latex] ­ 15.4 d
192 [latex]{\text{}}^{192}\text{Os}[/latex] 191.961 467 41.0%
77 Iridium 191 [latex]{\text{}}^{191}\text{Ir}[/latex] 190.960 584 37.3%
193 [latex]{\text{}}^{193}\text{Ir}[/latex] 192.962 917 62.7%
78 Platinum 195 [latex]{\text{}}^{195}\text{Pt}[/latex] 194.964 766 33.8%
79 Gold 197 [latex]{\text{}}^{197}\text{Au}[/latex] 196.966 543 100%
198 [latex]{\text{}}^{198}\text{Au}[/latex] 197.968 217 [latex]{\beta }^{-}[/latex] ­ 2.696 d
80 Mercury 199 [latex]{\text{}}^{199}\text{Hg}[/latex] 198.968 253 16.87%
202 [latex]{\text{}}^{202}\text{Hg}[/latex] 201.970 617 29.86%
81 Thallium 205 [latex]{\text{}}^{205}\text{Tl}[/latex] 204.974 401 70.48%
82 Lead 206 [latex]{\text{}}^{206}\text{Pb}[/latex] 205.974 440 24.1%
207 [latex]{\text{}}^{207}\text{Pb}[/latex] 206.975 872 22.1%
208 [latex]{\text{}}^{208}\text{Pb}[/latex] 207.976 627 52.4%
210 [latex]{\text{}}^{210}\text{Pb}[/latex] 209.984 163 [latex]\alpha ,\phantom{\rule{0.20em}{0ex}}{\beta }^{-}[/latex] ­ 22.3 y
211 [latex]{\text{}}^{211}\text{Pb}[/latex] 210.988 735 [latex]{\beta }^{-}[/latex] ­ 36.1 min
212 [latex]{\text{}}^{212}\text{Pb}[/latex] 211.991 871 [latex]{\beta }^{-}[/latex] ­ 10.64 h
83 Bismuth 209 [latex]{\text{}}^{209}\text{Bi}[/latex] 208.980 374 100%
211 [latex]{\text{}}^{211}\text{Bi}[/latex] 210.987 255 [latex]\alpha ,\phantom{\rule{0.20em}{0ex}}{\beta }^{-}[/latex] 2.14 min
84 Polonium 210 [latex]{\text{}}^{210}\text{Po}[/latex] 209.982 848 [latex]\alpha[/latex] 138.38 d
85 Astatine 218 [latex]{\text{}}^{218}\text{At}[/latex] 218.008 684 [latex]\alpha ,\phantom{\rule{0.20em}{0ex}}{\beta }^{-}[/latex] 1.6 s
86 Radon 222 [latex]{\text{}}^{222}\text{Rn}[/latex] 222.017 570 [latex]\alpha[/latex] 3.82 d
87 Francium 223 [latex]{\text{}}^{223}\text{Fr}[/latex] 223.019 733 [latex]\alpha ,\phantom{\rule{0.20em}{0ex}}{\beta }^{-}[/latex] 21.8 min
88 Radium 226 [latex]{\text{}}^{226}\text{Ra}[/latex] 226.025 402 [latex]\alpha[/latex] [latex]1\text{.}\text{60}×{\text{10}}^{3}\text{y}[/latex]
89 Actinium 227 [latex]{\text{}}^{227}\text{Ac}[/latex] 227.027 750 [latex]\alpha ,\phantom{\rule{0.20em}{0ex}}{\beta }^{-}[/latex] 21.8 y
90 Thorium 228 [latex]{\text{}}^{228}\text{Th}[/latex] 228.028 715 [latex]\alpha[/latex] 1.91 y
232 [latex]{\text{}}^{232}\text{Th}[/latex] 232.038 054 100%, [latex]\alpha[/latex] [latex]1\text{.}\text{41}×{\text{10}}^{\text{10}}\text{y}[/latex]
91 Protactinium 231 [latex]{\text{}}^{231}\text{Pa}[/latex] 231.035 880 [latex]\alpha[/latex] [latex]3\text{.}\text{28}×{\text{10}}^{4}\text{y}[/latex]
92 Uranium 233 [latex]{\text{}}^{233}\text{U}[/latex] 233.039 628 [latex]\alpha[/latex] [latex]1\text{.}\text{59}×{\text{10}}^{3}\text{y}[/latex]
235 [latex]{\text{}}^{235}\text{U}[/latex] 235.043 924 0.720%, [latex]\alpha[/latex] [latex]7\text{.}\text{04}×{\text{10}}^{8}\text{y}[/latex]
236 [latex]{\text{}}^{236}\text{U}[/latex] 236.045 562 [latex]\alpha[/latex] [latex]2\text{.}\text{34}×{\text{10}}^{7}\text{y}[/latex]
238 [latex]{\text{}}^{238}\text{U}[/latex] 238.050 784 99.2745%, [latex]\alpha[/latex] [latex]4\text{.}\text{47}×{\text{10}}^{9}\text{y}[/latex]
239 [latex]{\text{}}^{239}\text{U}[/latex] 239.054 289 [latex]{\beta }^{-}[/latex] ­ 23.5 min
93 Neptunium 239 [latex]{\text{}}^{239}\text{Np}[/latex] 239.052 933 [latex]{\beta }^{-}[/latex] ­ 2.355 d
94 Plutonium 239 [latex]{\text{}}^{239}\text{Pu}[/latex] 239.052 157 [latex]\alpha[/latex] [latex]2\text{.}\text{41}×{\text{10}}^{4}\text{y}[/latex]
95 Americium 243 [latex]{\text{}}^{243}\text{Am}[/latex] 243.061 375 [latex]\alpha ,[/latex] fission [latex]7\text{.}\text{37}×{\text{10}}^{3}\text{y}[/latex]
96 Curium 245 [latex]{\text{}}^{245}\text{Cm}[/latex] 245.065 483 [latex]\alpha[/latex] [latex]8\text{.}\text{50}×{\text{10}}^{3}\text{y}[/latex]
97 Berkelium 247 [latex]{\text{}}^{247}\text{Bk}[/latex] 247.070 300 [latex]\alpha[/latex] [latex]1\text{.}\text{38}×{\text{10}}^{3}\text{y}[/latex]
98 Californium 249 [latex]{\text{}}^{249}\text{Cf}[/latex] 249.074 844 [latex]\alpha[/latex] 351 y
99 Einsteinium 254 [latex]{\text{}}^{254}\text{Es}[/latex] 254.088 019 [latex]\alpha ,\phantom{\rule{0.20em}{0ex}}{\beta }^{-}[/latex] ­ 276 d
100 Fermium 253 [latex]{\text{}}^{253}\text{Fm}[/latex] 253.085 173 EC, [latex]\alpha[/latex] 3.00 d
101 Mendelevium 255 [latex]{\text{}}^{255}\text{Md}[/latex] 255.091 081 EC, [latex]\alpha[/latex] 27 min
102 Nobelium 255 [latex]{\text{}}^{255}\text{No}[/latex] 255.093 260 EC, [latex]\alpha[/latex] 3.1 min
103 Lawrencium 257 [latex]{\text{}}^{257}\text{Lr}[/latex] 257.099 480 EC, [latex]\alpha[/latex] 0.646 s
104 Rutherfordium 261 [latex]{\text{}}^{261}\text{Rf}[/latex] 261.108 690 [latex]\alpha[/latex] 1.08 min
105 Dubnium 262 [latex]{\text{}}^{262}\text{Db}[/latex] 262.113 760 [latex]\alpha ,[/latex] fission 34 s
106 Seaborgium 263 [latex]{\text{}}^{263}\text{Sg}[/latex] 263.11 86 [latex]\alpha ,[/latex] fission 0.8 s
107 Bohrium 262 [latex]{\text{}}^{262}\text{Bh}[/latex] 262.123 1 [latex]\alpha[/latex] 0.102 s
108 Hassium 264 [latex]{\text{}}^{264}\text{Hs}[/latex] 264.128 5 [latex]\alpha[/latex] 0.08 ms
109 Meitnerium 266 [latex]{\text{}}^{266}\text{Mt}[/latex] 266.137 8 [latex]\alpha[/latex] 3.4 ms

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