Appendix A. Atomic Masses

 

Table 1. 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
nn
1.008 665
β{\beta }^{-}
10.37 min
1 Hydrogen 1
1H{\text{}}^{1}\text{H}
1.007 825 99.985%
Deuterium 2
2H or D{\text{}}^{2}\text{H or D}
2.014 102 0.015%
Tritium 3
3H or T{\text{}}^{3}\text{H or T}
3.016 050
β{\beta }^{-}
12.33 y
2 Helium 3
3He{\text{}}^{3}\text{He}
3.016 030
1.38×104%1.38\times 10^{-4}\%
4
4He{\text{}}^{4}\text{He}
4.002 603
100%\approx 100\%
3 Lithium 6
6Li{\text{}}^{6}\text{Li}
6.015 121 7.5%
7
7Li{\text{}}^{7}\text{Li}
7.016 003 92.5%
4 Beryllium 7
7Be{\text{}}^{7}\text{Be}
7.016 928 EC 53.29 d
9
9Be{\text{}}^{9}\text{Be}
9.012 182 100%
5 Boron 10
10B{\text{}}^{10}\text{B}
10.012 937 19.9%
11
11B{\text{}}^{11}\text{B}
11.009 305 80.1%
6 Carbon 11
11C{\text{}}^{11}\text{C}
11.011 432 EC,
β+{\beta }^{+}
12
12C{\text{}}^{12}\text{C}
12.000 000 98.90%
13
13C{\text{}}^{13}\text{C}
13.003 355 1.10%
14
14C{\text{}}^{14}\text{C}
14.003 241
β{\beta }^{-}
5730 y
7 Nitrogen 13
13N{\text{}}^{13}\text{N}
13.005 738
β+{\beta }^{+}
9.96 min
14
14N{\text{}}^{14}\text{N}
14.003 074 99.63%
15
15N{\text{}}^{15}\text{N}
15.000 108 0.37%
8 Oxygen 15
15O{\text{}}^{15}\text{O}
15.003 065 EC,
β+{\beta }^{+}
122 s
16
16O{\text{}}^{16}\text{O}
15.994 915 99.76%
18
18O{\text{}}^{18}\text{O}
17.999 160 0.200%
9 Fluorine 18
18F{\text{}}^{18}\text{F}
18.000 937 EC,
β+{\beta }^{+}
1.83 h
19
19F{\text{}}^{19}\text{F}
18.998 403 100%
10 Neon 20
20Ne{\text{}}^{20}\text{Ne}
19.992 435 90.51%
22
22Ne{\text{}}^{22}\text{Ne}
21.991 383 9.22%
11 Sodium 22
22Na{\text{}}^{22}\text{Na}
21.994 434
β+{\beta }^{+}
2.602 y
23
23Na{\text{}}^{23}\text{Na}
22.989 767 100%
24
24Na{\text{}}^{24}\text{Na}
23.990 961
β{\beta }^{-}
14.96 h
12 Magnesium 24
24Mg{\text{}}^{24}\text{Mg}
23.985 042 78.99%
13 Aluminum 27
27Al{\text{}}^{27}\text{Al}
26.981 539 100%
14 Silicon 28
28Si{\text{}}^{28}\text{Si}
27.976 927 92.23% 2.62h
31
31Si{\text{}}^{31}\text{Si}
30.975 362
β{\beta }^{-}
15 Phosphorus 31
31P{\text{}}^{31}\text{P}
30.973 762 100%
32
32P{\text{}}^{32}\text{P}
31.973 907
β{\beta }^{-}
14.28 d
16 Sulfur 32
32S{\text{}}^{32}\text{S}
31.972 070 95.02%
35
35S{\text{}}^{35}\text{S}
34.969 031
β{\beta }^{-}
87.4 d
17 Chlorine 35
35Cl{\text{}}^{35}\text{Cl}
34.968 852 75.77%
37
37Cl{\text{}}^{37}\text{Cl}
36.965 903 24.23%
18 Argon 40
40Ar{\text{}}^{40}\text{Ar}
39.962 384 99.60%
19 Potassium 39
39K{\text{}}^{39}\text{K}
38.963 707 93.26%
40
40K{\text{}}^{40}\text{K}
39.963 999 0.0117%, EC,
β{\beta }^{-}
1.28×109y1\text{.}\text{28}\times {\text{10}}^{9}\text{y}
20 Calcium 40
40Ca{\text{}}^{40}\text{Ca}
39.962 591 96.94%
21 Scandium 45
45Sc{\text{}}^{45}\text{Sc}
44.955 910 100%
22 Titanium 48
48Ti{\text{}}^{48}\text{Ti}
47.947 947 73.8%
23 Vanadium 51
51V{\text{}}^{51}\text{V}
50.943 962 99.75%
24 Chromium 52
52Cr{\text{}}^{52}\text{Cr}
51.940 509 83.79%
25 Manganese 55
55Mn{\text{}}^{55}\text{Mn}
54.938 047 100%
26 Iron 56
56Fe{\text{}}^{56}\text{Fe}
55.934 939 91.72%
27 Cobalt 59
59Co{\text{}}^{59}\text{Co}
58.933 198 100%
60
60Co{\text{}}^{60}\text{Co}
59.933 819
β{\beta }^{-}
5.271 y
28 Nickel 58
58Ni{\text{}}^{58}\text{Ni}
57.935 346 68.27%
60
60Ni{\text{}}^{60}\text{Ni}
59.930 788 26.10%
29 Copper 63
63Cu{\text{}}^{63}\text{Cu}
62.939 598 69.17%
65
65Cu{\text{}}^{65}\text{Cu}
64.927 793 30.83%
30 Zinc 64
64Zn{\text{}}^{64}\text{Zn}
63.929 145 48.6%
66
66Zn{\text{}}^{66}\text{Zn}
65.926 034 27.9%
31 Gallium 69
69Ga{\text{}}^{69}\text{Ga}
68.925 580 60.1%
32 Germanium 72
72Ge{\text{}}^{72}\text{Ge}
71.922 079 27.4%
74
74Ge{\text{}}^{74}\text{Ge}
73.921 177 36.5%
33 Arsenic 75
75As{\text{}}^{75}\text{As}
74.921 594 100%
34 Selenium 80
80Se{\text{}}^{80}\text{Se}
79.916 520 49.7%
35 Bromine 79
79Br{\text{}}^{79}\text{Br}
78.918 336 50.69%
36 Krypton 84
84Kr{\text{}}^{84}\text{Kr}
83.911 507 57.0%
37 Rubidium 85
85Rb{\text{}}^{85}\text{Rb}
84.911 794 72.17%
38 Strontium 86
86Sr{\text{}}^{86}\text{Sr}
85.909 267 9.86%
88
88Sr{\text{}}^{88}\text{Sr}
87.905 619 82.58%
90
90Sr{\text{}}^{90}\text{Sr}
89.907 738
β{\beta }^{-}
­
28.8 y
39 Yttrium 89
89Y{\text{}}^{89}\text{Y}
88.905 849 100%
90
90Y{\text{}}^{90}\text{Y}
89.907 152
β{\beta }^{-}
­
64.1 h
40 Zirconium 90
90Zr{\text{}}^{90}\text{Zr}
89.904 703 51.45%
41 Niobium 93
93Nb{\text{}}^{93}\text{Nb}
92.906 377 100%
42 Molybdenum 98
98Mo{\text{}}^{98}\text{Mo}
97.905 406 24.13%
43 Technetium 98
98Tc{\text{}}^{98}\text{Tc}
97.907 215
β{\beta }^{-}
­
4.2×106y4\text{.}2\times {\text{10}}^{6}\text{y}
44 Ruthenium 102
102Ru{\text{}}^{102}\text{Ru}
101.904 348 31.6%
45 Rhodium 103
103Rh{\text{}}^{103}\text{Rh}
102.905 500 100%
46 Palladium 106
106Pd{\text{}}^{106}\text{Pd}
105.903 478 27.33%
47 Silver 107
107Ag{\text{}}^{107}\text{Ag}
106.905 092 51.84%
109
109Ag{\text{}}^{109}\text{Ag}
108.904 757 48.16%
48 Cadmium 114
114Cd{\text{}}^{114}\text{Cd}
113.903 357 28.73%
49 Indium 115
115In{\text{}}^{115}\text{In}
114.903 880 95.7%,
β{\beta }^{-}
­
4.4×1014y4\text{.}4\times {\text{10}}^{\text{14}}\text{y}
50 Tin 120
120Sn{\text{}}^{120}\text{Sn}
119.902 200 32.59%
51 Antimony 121
121Sb{\text{}}^{121}\text{Sb}
120.903 821 57.3%
52 Tellurium 130
130Te{\text{}}^{130}\text{Te}
129.906 229 33.8%,
β{\beta }^{-}
­
2.5×1021y2\text{.}5\times {\text{10}}^{\text{21}}\text{y}
53 Iodine 127
127I{\text{}}^{127}\text{I}
126.904 473 100%
131
131I{\text{}}^{131}\text{I}
130.906 114
β{\beta }^{-}
­
8.040 d
54 Xenon 132
132Xe{\text{}}^{132}\text{Xe}
131.904 144 26.9%
136
136Xe{\text{}}^{136}\text{Xe}
135.907 214 8.9%
55 Cesium 133
133Cs{\text{}}^{133}\text{Cs}
132.905 429 100%
134
134Cs{\text{}}^{134}\text{Cs}
133.906 696 EC,
β{\beta }^{-}
­
2.06 y
56 Barium 137
137Ba{\text{}}^{137}\text{Ba}
136.905 812 11.23%
138
138Ba{\text{}}^{138}\text{Ba}
137.905 232 71.70%
57 Lanthanum 139
139La{\text{}}^{139}\text{La}
138.906 346 99.91%
58 Cerium 140
140Ce{\text{}}^{140}\text{Ce}
139.905 433 88.48%
59 Praseodymium 141
141Pr{\text{}}^{141}\text{Pr}
140.907 647 100%
60 Neodymium 142
142Nd{\text{}}^{142}\text{Nd}
141.907 719 27.13%
61 Promethium 145
145Pm{\text{}}^{145}\text{Pm}
144.912 743 EC,
α\alpha
17.7 y
62 Samarium 152
152Sm{\text{}}^{152}\text{Sm}
151.919 729 26.7%
63 Europium 153
153Eu{\text{}}^{153}\text{Eu}
152.921 225 52.2%
64 Gadolinium 158
158Gd{\text{}}^{158}\text{Gd}
157.924 099 24.84%
65 Terbium 159
159Tb{\text{}}^{159}\text{Tb}
158.925 342 100%
66 Dysprosium 164
164Dy{\text{}}^{164}\text{Dy}
163.929 171 28.2%
67 Holmium 165
165Ho{\text{}}^{165}\text{Ho}
164.930 319 100%
68 Erbium 166
166Er{\text{}}^{166}\text{Er}
165.930 290 33.6%
69 Thulium 169
169Tm{\text{}}^{169}\text{Tm}
168.934 212 100%
70 Ytterbium 174
174Yb{\text{}}^{174}\text{Yb}
173.938 859 31.8%
71 Lutecium 175
175Lu{\text{}}^{175}\text{Lu}
174.940 770 97.41%
72 Hafnium 180
180Hf{\text{}}^{180}\text{Hf}
179.946 545 35.10%
73 Tantalum 181
181Ta{\text{}}^{181}\text{Ta}
180.947 992 99.98%
74 Tungsten 184
184W{\text{}}^{184}\text{W}
183.950 928 30.67%
75 Rhenium 187
187Re{\text{}}^{187}\text{Re}
186.955 744 62.6%,
β{\beta }^{-}
4.6×1010y4\text{.}6\times {\text{10}}^{\text{10}}\text{y}
76 Osmium 191
191Os{\text{}}^{191}\text{Os}
190.960 920
β{\beta }^{-}
­
15.4 d
192
192Os{\text{}}^{192}\text{Os}
191.961 467 41.0%
77 Iridium 191
191Ir{\text{}}^{191}\text{Ir}
190.960 584 37.3%
193
193Ir{\text{}}^{193}\text{Ir}
192.962 917 62.7%
78 Platinum 195
195Pt{\text{}}^{195}\text{Pt}
194.964 766 33.8%
79 Gold 197
197Au{\text{}}^{197}\text{Au}
196.966 543 100%
198
198Au{\text{}}^{198}\text{Au}
197.968 217
β{\beta }^{-}
­
2.696 d
80 Mercury 199
199Hg{\text{}}^{199}\text{Hg}
198.968 253 16.87%
202
202Hg{\text{}}^{202}\text{Hg}
201.970 617 29.86%
81 Thallium 205
205Tl{\text{}}^{205}\text{Tl}
204.974 401 70.48%
82 Lead 206
206Pb{\text{}}^{206}\text{Pb}
205.974 440 24.1%
207
207Pb{\text{}}^{207}\text{Pb}
206.975 872 22.1%
208
208Pb{\text{}}^{208}\text{Pb}
207.976 627 52.4%
210
210Pb{\text{}}^{210}\text{Pb}
209.984 163
α,β\alpha ,{\beta }^{-}
­
22.3 y
211
211Pb{\text{}}^{211}\text{Pb}
210.988 735
β{\beta }^{-}
­
36.1 min
212
212Pb{\text{}}^{212}\text{Pb}
211.991 871
β{\beta }^{-}
­
10.64 h
83 Bismuth 209
209Bi{\text{}}^{209}\text{Bi}
208.980 374 100%
211
211Bi{\text{}}^{211}\text{Bi}
210.987 255
α,β\alpha ,{\beta }^{-}
2.14 min
84 Polonium 210
210Po{\text{}}^{210}\text{Po}
209.982 848
α\alpha
138.38 d
85 Astatine 218
218At{\text{}}^{218}\text{At}
218.008 684
α,β\alpha ,{\beta }^{-}
1.6 s
86 Radon 222
222Rn{\text{}}^{222}\text{Rn}
222.017 570
α\alpha
3.82 d
87 Francium 223
223Fr{\text{}}^{223}\text{Fr}
223.019 733
α,β\alpha ,{\beta }^{-}
21.8 min
88 Radium 226
226Ra{\text{}}^{226}\text{Ra}
226.025 402
α\alpha
1.60×103y1\text{.}\text{60}\times {\text{10}}^{3}\text{y}
89 Actinium 227
227Ac{\text{}}^{227}\text{Ac}
227.027 750
α,β\alpha ,{\beta }^{-}
21.8 y
90 Thorium 228
228Th{\text{}}^{228}\text{Th}
228.028 715
α\alpha
1.91 y
232
232Th{\text{}}^{232}\text{Th}
232.038 054 100%,
α\alpha
1.41×1010y1\text{.}\text{41}\times {\text{10}}^{\text{10}}\text{y}
91 Protactinium 231
231Pa{\text{}}^{231}\text{Pa}
231.035 880
α\alpha
3.28×104y3\text{.}\text{28}\times {\text{10}}^{4}\text{y}
92 Uranium 233
233U{\text{}}^{233}\text{U}
233.039 628
α\alpha
1.59×103y1\text{.}\text{59}\times {\text{10}}^{3}\text{y}
235
235U{\text{}}^{235}\text{U}
235.043 924 0.720%,
α\alpha
7.04×108y7\text{.}\text{04}\times {\text{10}}^{8}\text{y}
236
236U{\text{}}^{236}\text{U}
236.045 562
α\alpha
2.34×107y2\text{.}\text{34}\times {\text{10}}^{7}\text{y}
238
238U{\text{}}^{238}\text{U}
238.050 784 99.2745%,
α\alpha
4.47×109y4\text{.}\text{47}\times {\text{10}}^{9}\text{y}
239
239U{\text{}}^{239}\text{U}
239.054 289
β{\beta }^{-}
­
23.5 min
93 Neptunium 239
239Np{\text{}}^{239}\text{Np}
239.052 933
β{\beta }^{-}
­
2.355 d
94 Plutonium 239
239Pu{\text{}}^{239}\text{Pu}
239.052 157
α\alpha
2.41×104y2\text{.}\text{41}\times {\text{10}}^{4}\text{y}
95 Americium 243
243Am{\text{}}^{243}\text{Am}
243.061 375
α\alpha
, fission
7.37×103y7\text{.}\text{37}\times {\text{10}}^{3}\text{y}
96 Curium 245
245Cm{\text{}}^{245}\text{Cm}
245.065 483
α\alpha
8.50×103y8\text{.}\text{50}\times {\text{10}}^{3}\text{y}
97 Berkelium 247
247Bk{\text{}}^{247}\text{Bk}
247.070 300
α\alpha
1.38×103y1\text{.}\text{38}\times {\text{10}}^{3}\text{y}
98 Californium 249
249Cf{\text{}}^{249}\text{Cf}
249.074 844
α\alpha
351 y
99 Einsteinium 254
254Es{\text{}}^{254}\text{Es}
254.088 019
α,β\alpha ,{\beta }^{-}
­
276 d
100 Fermium 253
253Fm{\text{}}^{253}\text{Fm}
253.085 173 EC,
α\alpha
3.00 d
101 Mendelevium 255
255Md{\text{}}^{255}\text{Md}
255.091 081 EC,
α\alpha
27 min
102 Nobelium 255
255No{\text{}}^{255}\text{No}
255.093 260 EC,
α\alpha
3.1 min
103 Lawrencium 257
257Lr{\text{}}^{257}\text{Lr}
257.099 480 EC,
α\alpha
0.646 s
104 Rutherfordium 261
261Rf{\text{}}^{261}\text{Rf}
261.108 690
α\alpha
1.08 min
105 Dubnium 262
262Db{\text{}}^{262}\text{Db}
262.113 760
α\alpha
, fission
34 s
106 Seaborgium 263
263Sg{\text{}}^{263}\text{Sg}
263.11 86
α\alpha
, fission
0.8 s
107 Bohrium 262
262Bh{\text{}}^{262}\text{Bh}
262.123 1
α\alpha
0.102 s
108 Hassium 264
264Hs{\text{}}^{264}\text{Hs}
264.128 5
α\alpha
0.08 ms
109 Meitnerium 266
266Mt{\text{}}^{266}\text{Mt}
266.137 8
α\alpha
3.4 ms

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