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

 

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Douglas College Physics 1207 Copyright © August 22, 2016 by OpenStax is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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