Table of radioelements (radioisotopes)

Element isotope old name
uranium 238U uranium
  234U uranium-II
protactinium 234Pa uranium-X2, brevium
thorium 234Th uranium-X1
  232Th thorium
  230Th ionium
  228Th radiothorium
  227Th radioactinium
actinium 228Ac mesothorium-II
  227Ac actinium
radium 228Ra mesothorium-I
  226Ra radium
  224Ra thorium-X
  223Ra actinium-X
radon 222Rn radium emanation, radon, niton
  220Rn thorium emanation, thoron
  219Rn actinium emanation, actinon
polonium 218Po radium-A
  216Po thorium-A
  215Po actinium-A
  214Po radium-C'
  212Po thorium-C'
  210Po radium-F, radiotellurium
bismuth 214Bi radium-C
  212Bi thorium-C
  211Bi actinium-C
  210Bi radium-E
lead 218Pb lead
  214Pb radium-B
  212Pb thorium-B
  211Pb actinium-B
  210Pb radium-D, radiolead
  210Pb lead
  208Pb lead
  206Pb lead
thallium 210Tl radium-C2
  208Tl thorium-D
  207Tl actinium-D

Isotopes can even have the same weight but differ in some other nuclear property. Two different 210Pb have different roles in the decay sequences: a stable 210Pb is one of the two end-products of the thorium sequence, while "radium-D" is an intermediate in the uranium series.