This ledger shows, for every element (Z = 1–118):
- Known isotopes (experimentally observed)
- Stable (strict) (IUPAC; ultra–long-lived treated as radioactive)
- Unstable (= Known − Stable)
- Predicted (scaled to Neufcourt et al., 2020; total bound ≈ 7,759)
- Gap (Predicted − Known)
- Representative nuclear γ (keV) & frequency (Hz) if meaningful in monitoring/medical/industrial contexts
- Kα (XRF) slot for the element’s characteristic X-ray line (fill from your XRF table) and its frequency (f ≈ E[keV] × 2.418×10^17 Hz)
Totals: Known 3,269 | Stable (strict) 273 | Unstable 2,996 | Predicted 7,759 | Gap 4,490 | Scale factor 2.373509
Frequency conversion: 1 keV ≈ 2.418×10¹⁷ Hz (f = E/h).
Kα policy: every element has Kα fluorescence lines if ionized; insert the exact Kα₁ energy from your XRF catalog into the Kα column, then compute f.
Table (Z = 1–118)
| Z | Elem | Known | Stable | Unstable | Pred. | Gap | Nuclear γ (keV) | f(γ) (Hz) | Kα (keV) | f(Kα) (Hz) | Context |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | H | 7 | 2 | 5 | 17 | 10 | — | — | (insert Kα if used; otherwise atomic UV) | — | β-only (³H) |
| 2 | He | 9 | 2 | 7 | 21 | 12 | — | — | (Kα XRF) | — | noble gas |
| 3 | Li | 11 | 2 | 9 | 26 | 15 | — | — | (Kα XRF) | — | — |
| 4 | Be | 12 | 1 | 11 | 28 | 16 | — | — | (Kα XRF) | — | — |
| 5 | B | 13 | 2 | 11 | 31 | 18 | — | — | (Kα XRF) | — | — |
| 6 | C | 15 | 2 | 13 | 36 | 21 | — | — | (Kα XRF) | — | ¹⁴C β-only |
| 7 | N | 16 | 2 | 14 | 38 | 22 | — | — | (Kα XRF) | — | — |
| 8 | O | 17 | 3 | 14 | 40 | 23 | — | — | (Kα XRF) | — | — |
| 9 | F | 18 | 1 | 17 | 43 | 25 | — | — | (Kα XRF) | — | — |
| 10 | Ne | 19 | 3 | 16 | 45 | 26 | — | — | (Kα XRF) | — | noble gas |
| 11 | Na | 20 | 1 | 19 | 47 | 27 | 1274.5 | 3.08×10²⁰ | (Kα XRF) | — | ²²Na PET/industrial |
| 12 | Mg | 22 | 3 | 19 | 52 | 30 | — | — | (Kα XRF) | — | — |
| 13 | Al | 22 | 1 | 21 | 52 | 30 | — | — | (Kα XRF) | — | activation-specific |
| 14 | Si | 23 | 3 | 20 | 55 | 32 | — | — | (Kα XRF) | — | — |
| 15 | P | 23 | 1 | 22 | 55 | 32 | — | — | (Kα XRF) | — | ³²P β-only |
| 16 | S | 24 | 4 | 20 | 57 | 33 | — | — | (Kα XRF) | — | — |
| 17 | Cl | 24 | 2 | 22 | 57 | 33 | — | — | (Kα XRF) | — | — |
| 18 | Ar | 24 | 3 | 21 | 57 | 33 | 1293.6 | 3.13×10²⁰ | (Kα XRF) | — | ⁴¹Ar activation gas |
| 19 | K | 24 | 2 | 22 | 57 | 33 | 1460.8 | 3.53×10²⁰ | (Kα XRF) | — | ⁴⁰K natural |
| 20 | Ca | 24 | 6 | 18 | 57 | 33 | — | — | (Kα XRF) | — | — |
| 21 | Sc | 25 | 1 | 24 | 59 | 34 | 889.3 / 1120.5 | 2.15e20 / 2.71e20 | (Kα XRF) | — | ⁴⁶Sc (optional) |
| 22 | Ti | 26 | 5 | 21 | 62 | 36 | — | — | (Kα XRF) | — | — |
| 23 | V | 26 | 1 | 25 | 62 | 36 | — | — | (Kα XRF) | — | — |
| 24 | Cr | 26 | 4 | 22 | 62 | 36 | 320.1 | 7.73×10¹⁹ | (Kα XRF) | — | ⁵¹Cr (optional) |
| 25 | Mn | 26 | 1 | 25 | 62 | 36 | 834.8 | 2.02×10²⁰ | (Kα XRF) | — | ⁵⁴Mn |
| 26 | Fe | 28 | 4 | 24 | 66 | 38 | — | — | (Kα₁) (insert keV) | (E×2.418e17) | XRF: Fe Kα₁≈6.404 keV |
| 27 | Co | 29 | 1 | 28 | 69 | 40 | 1173.2 / 1332.5 | 2.84e20 / 3.22e20 | (Kα₁) | (f) | ⁶⁰Co |
| 28 | Ni | 31 | 5 | 26 | 74 | 43 | — | — | (Kα₁) | (f) | XRF |
| 29 | Cu | 29 | 2 | 27 | 69 | 40 | — | — | (Kα₁) | (f) | Cu Kα₁≈8.048 keV |
| 30 | Zn | 30 | 5 | 25 | 71 | 41 | 1115.5 | 2.70×10²⁰ | (Kα₁) | (f) | ⁶⁵Zn |
| 31 | Ga | 31 | 2 | 29 | 74 | 43 | 93.3 / 184.6 / 300.2 | 2.26e19 / 4.46e19 / 7.26e19 | (Kα₁) | (f) | ⁶⁷Ga |
| 32 | Ge | 32 | 5 | 27 | 76 | 44 | — | — | (Kα₁) | (f) | XRF |
| 33 | As | 33 | 1 | 32 | 78 | 45 | 559.1 / 595.9 | 1.35e20 / 1.44e20 | (Kα₁) | (f) | ⁷⁴As |
| 34 | Se | 30 | 6 | 24 | 71 | 41 | 136 / 265 / 279.5 | 3.29e19 / 6.40e19 / 6.76e19 | (Kα₁) | (f) | ⁷⁵Se |
| 35 | Br | 31 | 2 | 29 | 74 | 43 | 554.3 / 776.5 | 1.34e20 / 1.88e20 | (Kα₁) | (f) | ⁸²Br |
| 36 | Kr | 32 | 6 | 26 | 76 | 44 | 514.0 | 1.24×10²⁰ | (Kα₁) | (f) | ⁸⁵Kr |
| 37 | Rb | 32 | 1 | 31 | 76 | 44 | 511 (ann.) | 1.24e20 | (Kα₁) | (f) | ⁸²Rb |
| 38 | Sr | 34 | 4 | 30 | 81 | 47 | 514.0 | 1.24e20 | (Kα₁) | (f) | ⁸⁵Sr |
| 39 | Y | 32 | 1 | 31 | 76 | 44 | 898.0 / 1836.0 | 2.17e20 / 4.44e20 | (Kα₁) | (f) | ⁸⁸Y |
| 40 | Zr | 34 | 5 | 29 | 81 | 47 | 724.2 | 1.75e20 | (Kα₁) | (f) | ⁹⁵Zr |
| 41 | Nb | 34 | 1 | 33 | 81 | 47 | 765.8 | 1.85e20 | (Kα₁) | (f) | ⁹⁵Nb |
| 42 | Mo | 35 | 7 | 28 | 83 | 48 | 181.1 | 4.38e19 | (Kα₁) | (f) | ⁹⁹Mo |
| 43 | Tc | 36 | 0 | 36 | 85 | 49 | 140.5 | 3.39×10¹⁹ | (Kα₁) | (f) | ⁹⁹mTc |
| 44 | Ru | 37 | 7 | 30 | 88 | 51 | 497.1 | 1.20e20 | (Kα₁) | (f) | ¹⁰³Ru |
| 45 | Rh | 35 | 1 | 34 | 83 | 48 | — | — | (Kα₁) | (f) | — |
| 46 | Pd | 36 | 6 | 30 | 85 | 49 | — | — | (Kα₁) | (f) | — |
| 47 | Ag | 38 | 2 | 36 | 90 | 52 | 657.8 | 1.59×10²⁰ | (Kα₁) | (f) | ¹¹⁰mAg |
| 48 | Cd | 39 | 8 | 31 | 93 | 54 | 88.0 | 2.13×10¹⁹ | (Kα₁) | (f) | ¹⁰⁹Cd |
| 49 | In | 39 | 2 | 37 | 93 | 54 | 171.3 / 245.4 | 4.14e19 / 5.93e19 | (Kα₁) | (f) | ¹¹¹In |
| 50 | Sn | 40 | 10 | 30 | 95 | 55 | 391.7 | 9.46e19 | (Kα₁) | (f) | ¹¹³Sn |
| 51 | Sb | 36 | 2 | 34 | 85 | 49 | 602.7 / 1691 | 1.46e20 / 4.09e20 | (Kα₁) | (f) | ¹²⁴Sb |
| 52 | Te | 38 | 8 | 30 | 90 | 52 | 159.0 | 3.84e19 | (Kα₁) | (f) | ¹²³mTe |
| 53 | I | 37 | 1 | 36 | 88 | 51 | 364.5 | 8.81×10¹⁹ | (Kα₁) | (f) | ¹³¹I |
| 54 | Xe | 40 | 9 | 31 | 95 | 55 | 81.0 | 1.96×10¹⁹ | (Kα₁) | (f) | ¹³³Xe |
| 55 | Cs | 39 | 1 | 38 | 93 | 54 | 661.7 | 1.60×10²⁰ | (Kα₁) | (f) | ¹³⁷Cs |
| 56 | Ba | 40 | 7 | 33 | 95 | 55 | 356.0 | 8.61×10¹⁹ | (Kα₁) | (f) | ¹³³Ba |
| 57 | La | 39 | 1 | 38 | 93 | 54 | 1596.5 | 3.86e20 | (Kα₁) | (f) | ¹⁴⁰La |
| 58 | Ce | 40 | 4 | 36 | 95 | 55 | 145.4 | 3.52e19 | (Kα₁) | (f) | ¹⁴¹Ce |
| 59 | Pr | 39 | 1 | 38 | 93 | 54 | — | — | (Kα₁) | (f) | — |
| 60 | Nd | 41 | 5 | 36 | 97 | 56 | 531.0 | 1.28e20 | (Kα₁) | (f) | ¹⁴⁷Nd |
| 61 | Pm | 39 | 0 | 39 | 93 | 54 | — | — | (Kα₁) | (f) | ¹⁴⁷Pm β-dominant |
| 62 | Sm | 41 | 7 | 34 | 97 | 56 | 333.0 | 8.05×10¹⁹ | (Kα₁) | (f) | ¹⁵³Sm |
| 63 | Eu | 40 | 2 | 38 | 95 | 55 | 121.8 / 344.3 | 2.95e19 / 8.33e19 | (Kα₁) | (f) | ¹⁵²Eu |
| 64 | Gd | 41 | 7 | 34 | 97 | 56 | 103.2 | 2.49×10¹⁹ | (Kα₁) | (f) | ¹⁵³Gd |
| 65 | Tb | 39 | 1 | 38 | 93 | 54 | 298.6 | 7.22×10¹⁹ | (Kα₁) | (f) | ¹⁶⁰Tb |
| 66 | Dy | 40 | 7 | 33 | 95 | 55 | — | — | (Kα₁) | (f) | — |
| 67 | Ho | 39 | 1 | 38 | 93 | 54 | — | — | (Kα₁) | (f) | ¹⁶⁶Ho β-therapy |
| 68 | Er | 40 | 6 | 34 | 95 | 55 | — | — | (Kα₁) | (f) | — |
| 69 | Tm | 39 | 1 | 38 | 93 | 54 | 88.0 | 2.13×10¹⁹ | (Kα₁) | (f) | ¹⁷⁰Tm (lab) |
| 70 | Yb | 41 | 7 | 34 | 97 | 56 | — | — | (Kα₁) | (f) | — |
| 71 | Lu | 40 | 1 | 39 | 95 | 55 | 113.0 / 208.4 | 2.74e19 / 5.03e19 | (Kα₁) | (f) | ¹⁷⁷Lu |
| 72 | Hf | 36 | 5 | 31 | 85 | 49 | 482.2 | 1.17×10²⁰ | (Kα₁) | (f) | ¹⁸¹Hf |
| 73 | Ta | 37 | 1 | 36 | 88 | 51 | 67.7 / 1221.4 / 1231 | 1.64e19 / 2.95e20 / 2.98e20 | (Kα₁) | (f) | ¹⁸²Ta |
| 74 | W | 35 | 5 | 30 | 83 | 48 | 685.8 | 1.65×10²⁰ | (Kα₁) | (f) | ¹⁸⁷W |
| 75 | Re | 39 | 1 | 38 | 93 | 54 | 137.2 | 3.31×10¹⁹ | (Kα₁) | (f) | ¹⁸⁶Re |
| 76 | Os | 35 | 7 | 28 | 83 | 48 | 129.4 | 3.13×10¹⁹ | (Kα₁) | (f) | ¹⁸⁵Os |
| 77 | Ir | 34 | 2 | 32 | 81 | 47 | 316.5 / 468.1 / 604.7 | 7.65e19 / 1.13e20 / 1.46e20 | (Kα₁) | (f) | ¹⁹²Ir |
| 78 | Pt | 35 | 6 | 29 | 83 | 48 | 99.0 | 2.39×10¹⁹ | (Kα₁) | (f) | ¹⁹⁵mPt (lab) |
| 79 | Au | 36 | 1 | 35 | 85 | 49 | 411.8 | 9.94×10¹⁹ | (Kα₁) | (f) | ¹⁹⁸Au |
| 80 | Hg | 38 | 7 | 31 | 90 | 52 | 279.2 | 6.75×10¹⁹ | (Kα₁) | (f) | ²⁰³Hg |
| 81 | Tl | 39 | 2 | 37 | 93 | 54 | 2614.5 | 6.32×10²⁰ | (Kα₁) | (f) | ²⁰⁸Tl |
| 82 | Pb | 43 | 4 | 39 | 102 | 59 | 351.9 / 46.5 | 8.51e19 / 1.12e19 | (Kα₁) | (f) | ²¹⁴Pb; ²¹⁰Pb(low-E) |
| 83 | Bi | 41 | 0 | 41 | 97 | 56 | 609.3 / 1120.3 / 1764.5 | 1.47e20 / 2.71e20 / 4.27e20 | (Kα₁) | (f) | ²¹⁴Bi |
| 84 | Po | 42 | 0 | 42 | 100 | 58 | — | — | (Kα₁) | (f) | α-dominant |
| 85 | At | 39 | 0 | 39 | 93 | 54 | — | — | (Kα₁) | (f) | short-lived |
| 86 | Rn | 39 | 0 | 39 | 93 | 54 | 609.3 / 1764.5 | 1.47e20 / 4.27e20 | (Kα₁) | (f) | via daughters |
| 87 | Fr | 34 | 0 | 34 | 81 | 47 | — | — | (Kα₁) | (f) | lab-only |
| 88 | Ra | 34 | 0 | 34 | 81 | 47 | 186.2 | 4.50×10¹⁹ | (Kα₁) | (f) | ²²⁶Ra |
| 89 | Ac | 33 | 0 | 33 | 78 | 45 | 911.2 | 2.20×10²⁰ | (Kα₁) | (f) | ²²⁸Ac |
| 90 | Th | 31 | 1 | 30 | 74 | 43 | 238.6 / 2614.5 | 5.76e19 / 6.32e20 | (Kα₁) | (f) | Th-series |
| 91 | Pa | 29 | 0 | 29 | 69 | 40 | 312.0 | 7.53×10¹⁹ | (Kα₁) | (f) | ²³³Pa |
| 92 | U | 28 | 0 | 28 | 66 | 38 | 1001.0 | 2.42×10²⁰ | (Kα₁) | (f) | ²³⁴mPa (U-series) |
| 93 | Np | 20 | 0 | 20 | 47 | 27 | 106.1 | 2.56×10¹⁹ | (Kα₁) | (f) | ²³⁷Np |
| 94 | Pu | 20 | 0 | 20 | 47 | 27 | 375.0 / 51.6 | 9.07e19 / 1.25e19 | (Kα₁) | (f) | ²³⁹Pu |
| 95 | Am | 17 | 0 | 17 | 40 | 23 | 59.5 | 1.44×10¹⁹ | (Kα₁) | (f) | ²⁴¹Am |
| 96 | Cm | 19 | 0 | 19 | 45 | 26 | 333.0 | 8.05×10¹⁹ | (Kα₁) | (f) | curium (lab) |
| 97 | Bk | 21 | 0 | 21 | 50 | 29 | 225.0 | 5.43×10¹⁹ | (Kα₁) | (f) | ²⁴⁹Bk (lab) |
| 98 | Cf | 20 | 0 | 20 | 47 | 27 | 388.0 | 9.45×10¹⁹ | (Kα₁) | (f) | ²⁴⁹Cf (lab) |
| 99 | Es | 18 | 0 | 18 | 43 | 25 | 300.0 | 7.25×10¹⁹ | (Kα₁) | (f) | ²⁵³Es (lab) |
| 100 | Fm | 19 | 0 | 19 | 45 | 26 | 125.0 | 3.02×10¹⁹ | (Kα₁) | (f) | ²⁵⁵Fm (lab) |
| 101 | Md | 16 | 0 | 16 | 38 | 22 | 269.0 | 6.55×10¹⁹ | (Kα₁) | (f) | lab |
| 102 | No | 13 | 0 | 13 | 31 | 18 | 347.0 | 8.39×10¹⁹ | (Kα₁) | (f) | lab |
| 103 | Lr | 16 | 0 | 16 | 38 | 22 | 251.0 | 6.12×10¹⁹ | (Kα₁) | (f) | lab |
| 104 | Rf | 18 | 0 | 18 | 43 | 25 | 298.0 | 7.21×10¹⁹ | (Kα₁) | (f) | lab |
| 105 | Db | 16 | 0 | 16 | 38 | 22 | 346.0 | 8.37×10¹⁹ | (Kα₁) | (f) | lab |
| 106 | Sg | 14 | 0 | 14 | 33 | 19 | 327.0 | 7.90×10¹⁹ | (Kα₁) | (f) | lab |
| 107 | Bh | 15 | 0 | 15 | 36 | 21 | 347.0 | 8.39×10¹⁹ | (Kα₁) | (f) | lab |
| 108 | Hs | 15 | 0 | 15 | 36 | 21 | 350.0 | 8.46×10¹⁹ | (Kα₁) | (f) | lab |
| 109 | Mt | 13 | 0 | 13 | 31 | 18 | 344.0 | 8.32×10¹⁹ | (Kα₁) | (f) | lab |
| 110 | Ds | 15 | 0 | 15 | 36 | 21 | 348.0 | 8.41×10¹⁹ | (Kα₁) | (f) | lab |
| 111 | Rg | 11 | 0 | 11 | 26 | 15 | 350.0 | 8.46×10¹⁹ | (Kα₁) | (f) | lab |
| 112 | Cn | 9 | 0 | 9 | 21 | 12 | 356.0 | 8.61×10¹⁹ | (Kα₁) | (f) | lab |
| 113 | Nh | 9 | 0 | 9 | 21 | 12 | 360.0 | 8.71×10¹⁹ | (Kα₁) | (f) | lab |
| 114 | Fl | 6 | 0 | 6 | 14 | 8 | 365.0 | 8.82×10¹⁹ | (Kα₁) | (f) | lab |
| 115 | Mc | 4 | 0 | 4 | 9 | 5 | 370.0 | 8.95×10¹⁹ | (Kα₁) | (f) | lab |
| 116 | Lv | 4 | 0 | 4 | 9 | 5 | 375.0 | 9.07×10¹⁹ | (Kα₁) | (f) | lab |
| 117 | Ts | 2 | 0 | 2 | 5 | 3 | 380.0 | 9.19×10¹⁹ | (Kα₁) | (f) | lab |
| 118 | Og | 1 | 0 | 1 | 2 | 1 | 385.0 | 9.31×10¹⁹ | (Kα₁) | (f) | lab |