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Z Element Total Isotopes Stable Unstable Running Total Running Stable Running Unstable 1 Hydrogen 7 2 5 7 2 5 2 Helium 9 2 7 16 4 12 3 Lithium 10 2 8 26 6 20 4 Beryllium 12 1 11 38 7 31 5 Boron 13 2 11 51 9 42 6 Carbon 15 2 13 66 11 55 7 Nitrogen 16 2 14 82 13 69 8 Oxygen 17 3 14 99 16 83 9 Fluorine 18 1 17 117 17 100 10 Neon 19 3 16 136 20 116 11 Sodium 20 1 19 156 21 135 12 Magnesium 21 3 18 177 24 153 13 Aluminum 22 1 21 199 25 174 14 Silicon 23 3 20 222 28 194 15 Phosphorus 24 1 23 246 29 217 16 Sulfur 25 4 21 271 33 238 17 Chlorine 26 2 24 297 35 262 18 Argon 27 3 24 324 38 286 19 Potassium 28 2 26 352 40 312 20 Calcium 29 6 23 381 46 335 21 Scandium 30 1 29 411 47 364 22 Titanium 31 5 26 442 52 390 23 Vanadium 32 1 31 474 53 421 24 Chromium 33 4 29 507 57 450 25 Manganese 34 1 33 541 58 483 26 Iron 35 4 31 576 62 514 27 Cobalt 36 1 35 612 63 549 28 Nickel 37 5 32 649 68 581 29 Copper 38 2 36 687 70 617 30 Zinc 39 5 34 726 75 651 31 Gallium 40 2 38 766 77 689 32 Germanium 41 5 36 807 82 725 33 Arsenic 42 1 41 849 83 766 34 Selenium 43 6 37 892 89 803 35 Bromine 44 2 42 936 91 845 36 Krypton 45 6 39 981 97 884 37 Rubidium 46 2 44 1,027 99 928 38 Strontium 47 4 43 1,074 103 971 39 Yttrium 48 1 47 1,122 104 1,018 40 Zirconium 49 5 44 1,171 109 1,062 … … … … … … … … 92 Uranium 28 3 25 ~2,963 251 2,712 93 Neptunium 20 0 20 ~2,983 251 2,732 94 Plutonium 23 0 23 ~3,006 251 2,755 95 Americium 17 0 17 ~3,023 251 2,772 96 Curium 20 0 20 ~3,043 251 2,792 97 Berkelium 19 0 19 ~3,062 251 2,811 98 Californium 19 0 19 ~3,081 251 2,830 99 Einsteinium 19 0 19 ~3,100 251 2,849 100 Fermium 18 0 18 ~3,118 251 2,867 101 Mendelevium 15 0 15 ~3,133 251 2,882 102 Nobelium 13 0 13 ~3,146 251 2,895 103 Lawrencium 15 0 15 ~3,161 251 2,910 104 Rutherfordium 14 0 14 ~3,175 251 2,924 105 Dubnium 15 0 15 ~3,190 251 2,939 106 Seaborgium 14 0 14 ~3,204 251 2,953 107 Bohrium 13 0 13 ~3,217 251 2,966 108 Hassium 13 0 13 ~3,230 251 2,979 109 Meitnerium 14 0 14 ~3,244 251 2,993 110 Darmstadtium 8 0 8 ~3,252 251 3,001 111 Roentgenium 13 0 13 ~3,265 251 3,014 112 Copernicium 12 0 12 ~3,277 251 3,026 113 Nihonium 9 0 9 ~3,286 251 3,035 114 Flerovium 10 0 10 ~3,296 251 3,045 115 Moscovium 8 0 8 ~3,304 251 3,053 116 Livermorium 7 0 7 ~3,311 251 3,060 117 Tennessine 4 0 4 ~3,315 251 3,064 118 Oganesson 2 0 2 ~3,317 251 3,066
🔎 Observations
Total isotopes identified (Z = 1–118): ~3,317 Stable isotopes: 252 Unstable isotopes: ~3,066 Most stable-rich elements: Tin (Sn, 10), Xenon (Xe, 9), Lead (Pb, 4 very long-lived, 1 primordial).Most isotopes overall: Tin, Xenon, Cesium, Uranium group, and Transuranics.No stable isotopes above Bismuth (Z = 83) , though some (e.g., Thorium-232, Uranium-238) are effectively primordial due to multi-billion year half-lives.
