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

 

License

Icon for the Creative Commons Attribution 4.0 International License

Appendix A Atomic Masses by OpenStax is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

Share This Book