[young] calculation OF ATOMIC DIAMETERS 51 



It will be noted that the elements which are found on the left- 

 hand side of any vertical row show a distinct tendency to be para- 

 magnetic. In fact, on examining the table more closely, it will be 

 seen that there are only three exceptions of any importance, namely. 

 Caesium in Group I, Strontium in Group II and Zirconium in Group 

 III, if it is assumed that in Group VIII the family of the rare gases 

 should be placed on the right-hand side of the vertical row and the 

 family of Iron metals and Platinum metals on the left-hand side. 



This deviation in the magnetic properties of these three elements 

 must be regarded as quite unusual, since in their other chemical and 

 physical properties they have been found to resemble strongly the 

 other members of their respective chemical families. Thus the 

 generalization was found to hold quite well throughout the periodic 

 system. 



On the other hand, as is readily seen, the elements which occurred 

 on the right-hand side of any vertical row are found to be diamagnetic 

 and there are no exceptions to this rule at all, taking the same alloca- 

 tion of the elements of Group VIII, as mentioned in the preceding 

 paragraph. Further, it is at once apparent that, in every chemical 

 family on the right-hand side of a vertical row, the diamagnetic 

 elements tend to become more diamagnetic with increase in atomic 

 weight. This property is especially well shown by the families 

 Copper, Silver, Gold; Zinc, Cadmium, Mercury; Arsenic, Antimony, 

 Bismuth; Chlorine, Bromine, Iodine and the noble gases Helium and 

 Argon . 



It is interesting to note that the recent investigations into the 

 crystal structure of the elements, which were initiated by Hull in 

 America and Deb^^e and Scherrer in Germany, have indicated a 

 somewhat similar state of afïairs for the relations of the crystal 

 structure of the element and its place in the periodic system. As 

 Hull^ has pointed out, as far as he was able to judge from the elements 

 that have been analysed, there is a distinct tendency for all the 

 elements in the same vertical column to have the same crystal struc- 

 ture. It is as yet too soon to attempt to explain in detail these 

 periodic crystalline, and also magnetic, properties of the elements by 

 any of the proposed atom models, but there can be no doubt but that 

 the magnetic susceptibility like crystal structure and the other 

 periodic physical properties of the elements must be represented by £ 

 similar periodic function as is their chemical behaviour. The present 

 theories in these matters would lead us to connect these properties 



"A. W. Hull, Jl. Franklin Institute, Feb., 1922. 



