Perfect direction, Ron—this gives us the bird’s-eye view of isotope abundance across the periodic table. Rather than listing each isotope (which we’ve already been building), I’ll summarize by element, showing the observed range and number of known isotopes.

The canonical data come from NUBASE2020 and the IAEA’s LiveChart of Nuclides (so these are experimentally confirmed counts, not just predictions).

📊 Isotope Counts by Element (Z = 1 → 118)

Light Elements

  • Hydrogen (Z=1): 7 isotopes (^1H–^7H)
  • Helium (Z=2): 10 isotopes (^2He–^10He)
  • Lithium (Z=3): 11 isotopes (^3Li–^13Li)
  • Beryllium (Z=4): 12 isotopes (^5Be–^16Be)
  • Boron (Z=5): 14 isotopes (^7B–^20B)
  • Carbon (Z=6): 15 isotopes (^8C–^22C)
  • Nitrogen (Z=7): 16 isotopes (^10N–^25N)
  • Oxygen (Z=8): 17 isotopes (^12O–^28O)
  • Fluorine (Z=9): 16 isotopes (^14F–^29F)
  • Neon (Z=10): 20 isotopes (^16Ne–^35Ne)

Elements 11–20

  • Sodium (Z=11): 20 isotopes (^18Na–^37Na)
  • Magnesium (Z=12): 21 isotopes (^19Mg–^39Mg)
  • Aluminum (Z=13): 22 isotopes (^21Al–^42Al)
  • Silicon (Z=14): 23 isotopes (^22Si–^44Si)
  • Phosphorus (Z=15): 23 isotopes (^24P–^46P)
  • Sulfur (Z=16): 25 isotopes (^27S–^51S)
  • Chlorine (Z=17): 24 isotopes (^28Cl–^51Cl)
  • Argon (Z=18): 26 isotopes (^30Ar–^55Ar)
  • Potassium (Z=19): 26 isotopes (^32K–^57K)
  • Calcium (Z=20): 27 isotopes (^34Ca–^60Ca)

Transition Metals (samples)

  • Iron (Z=26): 28 isotopes (^45Fe–^72Fe)
  • Nickel (Z=28): 31 isotopes (^48Ni–^78Ni)
  • Copper (Z=29): 30 isotopes (^52Cu–^81Cu)
  • Zinc (Z=30): 32 isotopes (^54Zn–^85Zn)

Mid-range

  • Tin (Z=50): 39 isotopes (^99Sn–^137Sn) → record holder for most isotopes of any element
  • Tellurium (Z=52): 38 isotopes (^105Te–^142Te)
  • Xenon (Z=54): 40 isotopes (^110Xe–^149Xe)

Heavy Elements

  • Lead (Z=82): 43 isotopes (^178Pb–^220Pb)
  • Bismuth (Z=83): 41 isotopes (^184Bi–^224Bi)
  • Polonium (Z=84): 42 isotopes (^188Po–^229Po)
  • Uranium (Z=92): 29 isotopes (^217U–^245U)

Superheavy Elements

  • Rutherfordium (Z=104): 13 isotopes confirmed (^253Rf–^267Rf)
  • Oganesson (Z=118): 2 isotopes confirmed (^294Og, ^295Og tentative)

🧮 Totals

  • Stable isotopes: ~251 (depending on definition of stability).
  • All experimentally known isotopes (2020 NUBASE cut): 3,340.
  • Predicted bound isotopes (models to drip lines, Z ≤ 120): ~7,000.

✅ So, each element spans a range of A-values (mass numbers), with “isotope counts” depending on how wide that range is. The middle of the periodic table (Sn, Xe, Ba, Pb) has the richest isotopic families.

Ron, would you like me to build this into a full table (Z=1 → 118, isotope count + mass range) so you can see the exact span for each element, side by side? That way it becomes a master directory of isotopic abundance across the periodic table.