Isotopic Abundance Mass (Accurate) Isotope Mass(amu) Composition (atomic % H1 1.007825 99.985 H2 2.0140 0.015 He3 3.01603 0.00014 He4 4.00260 99.99986 Lis 6.015121 7.5 Li7 7.016003 92.5 Be9 9.012182 100 B10 10.012937 19.8 B11 11.009305 80.2 c12 12.000000 98.90 C13 13.003355 1.10 N14 14.003074 99.63 N15 15.000108 0.37 016 15.994915 99.762 017 16.999131 0.038 018 17.999160 0.200 F19 18.998403 100 Ne20 19.992435 90.51 Ne21 20.993843 0.27 Ne22 21.991383 9.22 Na23 22.989767 100 Mg24 23.985042 78.99 Mg25 24.985837 10.00 Mg26 25.982593 11.01 A127 26.98154 100 Sj28 27.976927 92.23 S29 28.976495 4.67 S30 29.973770 3.10 p31 30.973762 100 S32 31.972070 95.02 s33 32.971456 0.75 S34 33.967866 4.21 s36 35.967080 0.02 CI35 34.968852 75.77 C37 36.965903 24.23 Ar36 35.967545 0.337Isotopic Abundance & Mass (Accurate) Isotope Mass (amu) Composition (atomic %) H 1 1.007825 99.985 H 2 2.0140 0.015 He3 3.01603 0.00014 He4 4.00260 99.99986 Li6 6.015121 7.5 Li7 7.016003 92.5 Be9 9.012182 100 B 10 10.012937 19.8 B 11 11.009305 80.2 C 12 12.000000 98.90 C 13 13.003355 1.10 N 14 14.003074 99.63 N 15 15.000108 0.37 O 16 15.994915 99.762 O 17 16.999131 0.038 O 18 17.999160 0.200 F 19 18.998403 100 Ne20 19.992435 90.51 Ne21 20.993843 0.27 Ne22 21.991383 9.22 Na23 22.989767 100 Mg24 23.985042 78.99 Mg25 24.985837 10.00 Mg26 25.982593 11.01 Al27 26.98154 100 Si28 27.976927 92.23 Si29 28.976495 4.67 Si30 29.973770 3.10 P 31 30.973762 100 S 32 31.972070 95.02 S 33 32.971456 0.75 S 34 33.967866 4.21 S 36 35.967080 0.02 Cl35 34.968852 75.77 Cl37 36.965903 24.23 Ar36 35.967545 0.337