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.