Abundances of the isotopes

element Z symbol A abundance mass excess

hydrogen 1 H 1 99.9885 7.289

2 0.0151 13.136

helium 2 He 3 0.000138 14.931

4 99.999863 2.425

lithium 3 Li 6 7.59 14.086

7 92.41 14.908

beryllium 4 Be 9 100 11.348

boron 5 B 10 19.9 12.051

11 80.1 8.668

carbon 6 C 12 98.93 0

13 1.07 3.125

nitrogen 7 N 14 99.632 2.863

15 0.368 0.101

oxygen 8 O 16 99.757 −4.737

17 0.038 −0.809

18 0.205 −0.782

fluorine 9 F 19 100 −1.487

neon 10 Ne 20 90.48 −7.042

21 0.27 −5.732

22 9.25 −8.024

sodium 11 Na 23 100 −9.529

magnesium 12 Mg 24 78.99 −13.933

25 10.00 −13.193

26 11.01 −16.214

aluminum 13 Al 27 100 −17.197

silicon 14 Si 28 92.2297 −21.493

29 4.6832 −21.895

30 3.0872 −24.433

phosphorus 15 P 31 100 −24.441

sulfur 16 S 32 94.93 −26.016

33 0.76 −26.586

34 4.29 −29.932

36 0.02 −30.664

chlorine 17 Cl 35 75.78 −29.014

37 24.22 −31.762

argon 18 Ar 36 0.3365 −30.230

38 0.0632 −34.715

40 99.6003 −35.040

potassium 19 K 39 93.2581 −33.807

40 0.0117 −33.535

41 6.7302 −35.559

calcium 20 Ca 40 96.941 −34.846

42 0.647 −38.547

43 0.135 −38.408

44 2.086 −41.469

46 0.004 −43.135

48 0.187 −44.215

scandium 21 Sc 45 100 −41.069

titanium 22 Ti 46 8.25 −44.125

47 7.44 −44.932

48 73.72 −48.487

49 5.41 −48.558

50 5.18 −51.426

vanadium 23 V 50 0.250 −49.218

51 99.750 −52.198

chromium 24 Cr 50 4.345 −50.254

52 83.789 −55.413

53 9.501 −55.281

54 2.365 −56.928

manganese 25 Mn 55 100 −57.706

iron 26 Fe 54 5.845 −56.248

56 91.754 −60.601

57 2.119 −60.176

58 0.282 −62.149

cobalt 27 Co 59 100 −62.224

nickel 28 Ni 58 68.0769 −60.223

60 26.2231 −64.468

61 1.1399 −64.217

62 3.6345 −66.743

64 0.9256 −67.096

copper 29 Cu 63 69.17 −65.576

65 30.83 −67.260

zinc 30 Zn 64 48.63 −66.000

66 27.90 −68.896

67 4.10 −67.877

68 18.75 −70.004

70 0.62 −69.559

gallium 31 Ga 69 60.108 −69.321

71 39.892 −70.137

germanium 32 Ge 70 20.84 −70.560

72 27.54 −72.586

73 7.73 −71.299

74 36.28 −73.422

76 7.61 −73.213

arsenic 33 As 75 100 −73.032

selenium 34 Se 74 0.89 −72.213

76 9.37 −75.252

77 7.63 −74.599

78 23.77 −77.026

80 49.61 −77.759

82 8.73 −77.593

bromine 35 Br 79 50.69 −76.068

81 49.31 −77.974

krypton 36 Kr 78 0.35 −74.160

80 2.28 −77.893

82 11.58 −80.589

83 11.49 −79.982

84 57.00 −82.431

86 17.30 −83.266

rubidium 37 Rb 85 72.17 −82.168

87 27.83 −84.595

strontium 38 Sr 84 0.56 −80.644

86 9.86 −84.522

87 7.00 −84.878

88 82.58 −87.920

yttrium 39 Y 89 100 −87.702

zirconium 40 Zr 90 51.45 −88.768

91 11.22 −87.891

92 17.15 −88.455

94 17.38 −87.266

96 2.80 −85.441

niobium 41 Nb 93 100 −87.209

molybdenum 42 Mo 92 14.84 −86.805

94 9.25 −88.410

95 15.92 −87.708

96 16.68 −88.791

97 9.55 −87.541

98 24.13 −88.112

100 9.63 −86.184

ruthenium 44 Ru 96 5.54 −86.072

98 1.87 −88.224

99 12.76 −87.617

100 12.60 −89.219

101 17.06 −87.950

102 31.55 −89.098

104 18.62 −88.091

rhodium 45 Rh 103 100 −88.022

palladium 46 Pd 102 1.020 −87.926

104 11.14 −89.391

105 22.33 −88.414

106 27.33 −89.905

108 26.46 −89.522

110 11.72 −88.350

silver 47 Ag 107 51.8392 −88.405

109 48.1608 −88.720

cadmium 48 Cd 106 1.25 −87.134

108 0.89 −89.253

110 12.49 −90.350

111 12.80 −89.254

112 24.13 −90.581

113 12.22 −89.050

114 28.73 −90.021

116 7.49 −88.720

indium 49 In 113 4.288 −89.366

115 95.712 −89.537

tin 50 Sn 112 0.973 −88.659

114 0.659 −90.558

115 0.339 −90.033

116 14.536 −91.525

117 7.676 −90.398

118 24.223 −91.653

119 8.585 −90.067

120 32.593 −91.103

122 4.629 −89.944

124 5.789 −88.236

antimony 51 Sb 121 57.213 −89.593

123 42.787 −89.222

tellurium 52 Te 120 0.096 −89.405

122 2.603 −90.311

123 0.908 −89.169

124 4.816 −90.523

125 7.139 −89.028

126 18.952 −90.070

128 31.687 −88.994

130 33.799 −87.353

iodine 53 I 127 100 −88.987

xenon 54 Xe 124 0.08913 −87.658

126 0.08880 −89.173

128 1.91732 −89.861

129 26.43964 −89.697

130 4.08271 −89.881

131 21.17961 −88.416

132 26.89157 −89.280

134 10.44232 −88.124

136 8.86590 −86.424

cesium 55 Cs 133 100 −88.076

barium 56 Ba 130 0.1058 −87.271

132 0.1012 −88.440

134 2.417 −88.954

135 6.592 −87.856

136 7.853 −88.892

137 11.232 −87.727

138 71.699 −88.267

lanthanum 57 La 138 0.09017 −86.529

139 99.91 −87.236

cerium 58 Ce 136 0.186 −86.500

138 0.251 −87.574

140 88.449 −88.088

142 11.114 −84.543

praseodymium 59 Pr 141 100 −86.026

neodymium 60 Nd 142 27.16 −85.960

143 12.18 −84.012

144 23.83 −83.758

145 8.30 −81.442

146 17.17 −80.936

148 5.74 −77.418

150 5.62 −73.694

samarium 62 Sm 144 3.0734 −81.976

147 14.9934 −79.276

148 11.2406 −79.347

149 13.8189 −77.147

150 7.3796 −77.061

152 26.7421 −74.773

154 22.7520 −72.465

europium 63 Eu 151 47.810 −74.663

153 52.190 −73.377

gadolinium 64 Gd 152 0.2029 −74.717

154 2.1809 −73.716

155 14.7998 −72.080

156 20.4664 −72.545

157 15.6518 −70.834

158 24.8347 −70.700

160 21.8635 −67.952

terbium 65 Tb 159 100 −69.542

dysprosium 66 Dy 156 0.056 −70.534

158 0.096 −70.417

160 2.34 −69.682

161 18.91 −68.065

162 25.51 −68.190

163 24.90 −66.390

164 28.19 −65.977

holmium 67 Ho 165 100 −64.907

erbium 68 Er 162 0.137 −66.346

164 1.609 −65.953

166 33.61 −64.934

167 22.93 −63.299

168 26.79 −62.999

170 14.93 −60.118

thulium 69 Tm 169 100 −61.282

ytterbium 70 Yb 168 0.127 −61.577

170 3.04 −60.772

171 14.28 −59.315

172 21.83 −59.264

173 16.13 −57.560

174 31.83 −56.953

176 12.76 −53.497

lutetium 71 Lu 175 97.416 −55.174

176 2.584 −53.391

hafnium 72 Hf 174 0.1620 −55.852

176 5.604 −54.584

177 18.5953 −52.890

178 27.811 −52.445

179 13.6210 −50.473

180 35.0802 −49.790

tantalum 73 Ta 180 0.0123 −48.935

181 99.9877 −48.441

tungsten 74 W 180 0.1198 −49.643

182 26.4985 −48.246

183 14.3136 −46.366

184 30.6422 −45.706

186 28.4259 −42.511

rhenium 75 Re 185 37.398 −43.821

187 62.602 −41.218

osmium 76 Os 184 0.0197 −44.254

186 1.5859 −42.999

187 1.9644 −41.220

188 13.2434 −41.138

189 16.1466 −38.988

190 26.2584 −38.708

192 40.7815 −35.882

iridium 77 Ir 191 37.272 −36.709

193 62.728 −34.536

platinum 78 Pt 190 0.013634 −37.325

192 0.782659 −36.296

194 32.96700 −34.779

195 33.831557 −32.812

196 25.24166 −32.663

198 7.16349 −29.923

gold 79 Au 197 100 −31.157

mercury 80 Hg 196 0.15344 −31.843

198 9.968 −30.970

199 16.873 −29.563

200 23.096 −29.520

201 13.181 −27.679

202 29.863 −27.362

204 6.865 −24.707

thallium 81 Tl 203 29.524 −25.775

205 70.476 −23.834

lead 82 Pb 204 1.4245 −25.123

206 24.1447 −23.801

207 22.0827 −22.467

208 52.3481 −21.764

bismuth 83 Bi 209 100 −18.273

thorium 90 Th 232 100 35.444

uranium 92 U 234 0.00548 38.141

235 0.7200 40.914

238 99.2745 47.304

Sources: G. Audi and A.H. Wapstra, "The 1995 Update to Atomic Mass Evaluation," Nuclear Physics A595, 409–480 (1995). K.J.R. Rosman and P.D.P. Taylor, "Isotopic Compositions of the Elements 1997," J. Phys. Chem. Ref. Data 27, 1275–1285 (1995).