156 



A Table of the Radioactive Elements. 



figure 1, in wliicli the branching off of the actinium series is 

 according to Soddy*. From the figure can be derived the 

 partial structural formula of each of the radioactive isotopes. 

 Thus the number of helium particles (and also the atomic 



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Fig. 1. 



61 82 83 81 85 86 87 

 Tl Pb Bi ?o N* 



88 89 90 91 92 

 Ra fie Th Bv U 



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weight) is the same for each isotope lying on the same 

 southwest to northeast axis ; the number of electrons in 

 the unstable next inner ring (E;) is the same for each 

 member on the same northwest to southeast axis ; the 

 number of valency electrons (E w ) are shown on the north to 

 south axis, and the total "metastasic" electrons (E m = E t -+ E„) 

 are the same for each substance on the same east to west 

 axis. In the partial atom-structural formula the nucleus u 

 for uranium nucleus with atomic weight 206'4, and t for 

 thorium nucleus of atomic weight 208*2, contains the 

 unknown number of helium nuclei and electrons and 

 indicates respectively lead from uranium and lead from 

 thorium. To this nucleus are added the number of He, E*, 



* Loc. cit. 



