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Physics LibreTexts

Chapter 15: Atomic Masses

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    Mar 12, 2024
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Table C⁢h⁡a⁢p⁢t⁢e⁢r⁢15.1: 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 n 1.008 665 β− 10.37 min
1 Hydrogen 1 1⁢H 1.007 825 99.985%  
  Deuterium 2 2⁢H or D 2.014 102 0.015%  
  Tritium 3 3⁢H or T 3.016 050 β− 12.33 y
2 Helium 3 3⁢He 3.016 030 1.38×10−4%  
    4 4⁢He 4.002 603 ≈100%  
3 Lithium 6 6⁢Li 6.015 121 7.5%  
    7 7⁢Li 7.016 003 92.5%  
4 Beryllium 7 7⁢Be 7.016 928 EC 53.29 d
    9 9⁢Be 9.012 182 100%  
5 Boron 10 10⁢ B 10.012 937 19.9%  
    11 11⁢ B 11.009 305 80.1%  
6 Carbon 11 11⁢C 11.011 432 EC, β+  
    12 12⁢C 12.000 000 98.90%  
    13 13⁢C 13.003 355 1.10%  
    14 14⁢C 14.003 241 β− 5730 y
7 Nitrogen 13 13⁢ N 13.005 738 β+ 9.96 min
    14 14⁢ N 14.003 074 99.63%  
    15 15⁢ N 15.000 108 0.37%  
8 Oxygen 15 15⁢O 15.003 065 EC, β+ 122 s
    16 16⁢O 15.994 915 99.76%  
    18 18⁢O 17.999 160 0.200%  
9 Fluorine 18 18⁢ F 18.000 937 EC, β+ 1.83 h
    19 19⁢ F 18.998 403 100%  
10 Neon 20 20⁢Ne 19.992 435 90.51%  
    22 22⁢Ne 21.991 383 9.22%  
11 Sodium 22 22⁢Na 21.994 434 β+ 2.602 y
    23 23⁢Na 22.989 767 100%  
    24 24⁢Na 23.990 961 β− 14.96 h
12 Magnesium 24 24⁢Mg 23.985 042 78.99%  
13 Aluminum 27 27⁢Al 26.981 539 100%  
14 Silicon 28 28⁢Si 27.976 927 92.23% 2.62h
    31 31⁢Si 30.975 362 β−  
15 Phosphorus 31 31⁢P 30.973 762 100%  
    32 32⁢P 31.973 907 β− 14.28 d
16 Sulfur 32 32⁢S 31.972 070 95.02%  
    35 35⁢S 34.969 031 β− 87.4 d
17 Chlorine 35 35⁢Cl 34.968 852 75.77%  
    37 37⁢Cl 36.965 903 24.23%  
18 Argon 40 40⁢Ar 39.962 384 99.60%  
19 Potassium 39 39⁢ K 38.963 707 93.26%  
    40 40⁢ K 39.963 999 0.0117%, EC, β− 1.28×109⁢y
20 Calcium 40 40⁢Ca 39.962 591 96.94%  
21 Scandium 45 45⁢Sc 44.955 910 100%  
22 Titanium 48 48⁢Ti 47.947 947 73.8%  
23 Vanadium 51 51⁢ V 50.943 962 99.75%  
24 Chromium 52 52⁢Cr 51.940 509 83.79%  
25 Manganese 55 55⁢Mn 54.938 047 100%  
26 Iron 56 56⁢Fe 55.934 939 91.72%  
27 Cobalt 59 59⁢Co 58.933 198 100%  
    60 60⁢Co 59.933 819 β− 5.271 y
28 Nickel 58 58⁢Ni 57.935 346 68.27%  
    60 60⁢Ni 59.930 788 26.10%  
29 Copper 63 63⁢Cu 62.939 598 69.17%  
    65 65⁢Cu 64.927 793 30.83%  
30 Zinc 64 64⁢Zn 63.929 145 48.6%  
    66 66⁢Zn 65.926 034 27.9%  
31 Gallium 69 69⁢Ga 68.925 580 60.1%  
32 Germanium 72 72⁢Ge 71.922 079 27.4%  
    74 74⁢Ge 73.921 177 36.5%  
33 Arsenic 75 75⁢As 74.921 594 100%  
34 Selenium 80 80⁢Se 79.916 520 49.7%  
35 Bromine 79 79⁢Br 78.918 336 50.69%  
36 Krypton 84 84⁢Kr 83.911 507 57.0%  
37 Rubidium 85 85⁢Rb 84.911 794 72.17%  
38 Strontium 86 86⁢Sr 85.909 267 9.86%  
    88 88⁢Sr 87.905 619 82.58%  
    90 90⁢Sr 89.907 738 β− ­ 28.8 y
39 Yttrium 89 89⁢Y 88.905 849 100%  
    90 90⁢Y 89.907 152 β− ­ 64.1 h
40 Zirconium 90 90⁢Zr 89.904 703 51.45%  
41 Niobium 93 93⁢Nb 92.906 377 100%  
42 Molybdenum 98 98⁢Mo 97.905 406 24.13%  
43 Technetium 98 98⁢Tc 97.907 215 β− ­ 4.2×106⁢y
44 Ruthenium 102 102⁢Ru 101.904 348 31.6%  
45 Rhodium 103 103⁢Rh 102.905 500 100%  
46 Palladium 106 106⁢Pd 105.903 478 27.33%  
47 Silver 107 107⁢Ag 106.905 092 51.84%  
    109 109⁢Ag 108.904 757 48.16%  
48 Cadmium 114 114⁢Cd 113.903 357 28.73%  
49 Indium 115 115⁢In 114.903 880 95.7%, β− ­ 4.4×1014⁢y
50 Tin 120 120⁢Sn 119.902 200 32.59%  
51 Antimony 121 121⁢Sb 120.903 821 57.3%  
52 Tellurium 130 130⁢Te 129.906 229 33.8%, β− ­ 2.5×1021⁢y
53 Iodine 127 127⁢I 126.904 473 100%  
    131 131⁢I 130.906 114 β− ­ 8.040 d
54 Xenon 132 132⁢Xe 131.904 144 26.9%  
    136 136⁢Xe 135.907 214 8.9%  
55 Cesium 133 133⁢Cs 132.905 429 100%  
    134 134⁢Cs 133.906 696 EC, β− ­ 2.06 y
56 Barium 137 137⁢Ba 136.905 812 11.23%  
    138 138⁢Ba 137.905 232 71.70%  
57 Lanthanum 139 139⁢La 138.906 346 99.91%  
58 Cerium 140 140⁢Ce 139.905 433 88.48%  
59 Praseodymium 141 141⁢Pr 140.907 647 100%  
60 Neodymium 142 142⁢Nd 141.907 719 27.13%  
61 Promethium 145 145⁢Pm 144.912 743 EC, α 17.7 y
62 Samarium 152 152⁢Sm 151.919 729 26.7%  
63 Europium 153 153⁢Eu 152.921 225 52.2%  
64 Gadolinium 158 158⁢Gd 157.924 099 24.84%  
65 Terbium 159 159⁢Tb 158.925 342 100%  
66 Dysprosium 164 164⁢Dy 163.929 171 28.2%  
67 Holmium 165 165⁢Ho 164.930 319 100%  
68 Erbium 166 166⁢Er 165.930 290 33.6%  
69 Thulium 169 169⁢Tm 168.934 212 100%  
70 Ytterbium 174 174⁢Yb 173.938 859 31.8%  
71 Lutecium 175 175⁢Lu 174.940 770 97.41%  
72 Hafnium 180 180⁢Hf 179.946 545 35.10%  
73 Tantalum 181 181⁢Ta 180.947 992 99.98%  
74 Tungsten 184 184⁢W 183.950 928 30.67%  
75 Rhenium 187 187⁢Re 186.955 744 62.6%, β− 4.6×1010⁢y
76 Osmium 191 191⁢Os 190.960 920 β− ­ 15.4 d
    192 192⁢Os 191.961 467 41.0%  
77 Iridium 191 191⁢Ir 190.960 584 37.3%  
    193 193⁢Ir 192.962 917 62.7%  
78 Platinum 195 195⁢Pt 194.964 766 33.8%  
79 Gold 197 197⁢Au 196.966 543 100%  
    198 198⁢Au 197.968 217 β− ­ 2.696 d
80 Mercury 199 199⁢Hg 198.968 253 16.87%  
    202 202⁢Hg 201.970 617 29.86%  
81 Thallium 205 205⁢Tl 204.974 401 70.48%  
82 Lead 206 206⁢Pb 205.974 440 24.1%  
    207 207⁢Pb 206.975 872 22.1%  
    208 208⁢Pb 207.976 627 52.4%  
    210 210⁢Pb 209.984 163 α,β− 22.3 y
    211 211⁢Pb 210.988 735 β− ­ 36.1 min
    212 212⁢Pb 211.991 871 β− ­ 10.64 h
83 Bismuth 209 209⁢Bi 208.980 374 100%  
    211 211⁢Bi 210.987 255 α,β− 2.14 min
84 Polonium 210 210⁢Po 209.982 848 α 138.38 d
85 Astatine 218 218⁢At 218.008 684 α,β− 1.6 s
86 Radon 222 222⁢Rn 222.017 570 α 3.82 d
87 Francium 223 223⁢Fr 223.019 733 α,β− 21.8 min
88 Radium 226 226⁢Ra 226.025 402 α 1.60×103⁢y
89 Actinium 227 227⁢Ac 227.027 750 α,β− 21.8 y
90 Thorium 228 228⁢Th 228.028 715 α 1.91 y
    232 232⁢Th 232.038 054 100%, α 1.41×1010⁢y
91 Protactinium 231 231⁢ Pa 231.035 880 α 3.28×104⁢y
92 Uranium 233 233⁢U 233.039 628 α 1.59×103⁢y
    235 235⁢U 235.043 924 0.720%, α 7.04×108⁢y
    236 236⁢U 236.045 562 α 2.34×107⁢y
    238 238⁢U 238.050 784 99.2745%, α 4.47×109⁢y
    239 239⁢U 239.054 289 β− ­ 23.5 min
93 Neptunium 239 239⁢Np 239.052 933 β− ­ 2.355 d
94 Plutonium 239 239⁢Pu 239.052 157 α 2.41×104⁢y
95 Americium 243 243⁢Am 243.061 375 α, fission 7.37×103⁢y
96 Curium 245 245⁢Cm 245.065 483 α 8.50×103⁢y
97 Berkelium 247 247⁢Bk 247.070 300 α 1.38×103⁢y
98 Californium 249 249⁢Cf 249.074 844 α 351 y
99 Einsteinium 254 254⁢Es 254.088 019 α,β− 276 d
100 Fermium 253 253⁢Fm 253.085 173 EC, α 3.00 d
101 Mendelevium 255 255⁢Md 255.091 081 EC, α 27 min
102 Nobelium 255 255⁢No 255.093 260 EC, α 3.1 min
103 Lawrencium 257 257⁢Lr 257.099 480 EC, α 0.646 s
104 Rutherfordium 261 261⁢Rf 261.108 690 α 1.08 min
105 Dubnium 262 262⁢Db 262.113 760 α, fission 34 s
106 Seaborgium 263 263⁢Sg 263.11 86 α, fission 0.8 s
107 Bohrium 262 262⁢Bh 262.123 1 α 0.102 s
108 Hassium 264 264⁢Hs 264.128 5 α 0.08 ms
109 Meitnerium 266 266⁢Mt 266.137 8 α 3.4 ms

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