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

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

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