8 STROMEYER, Grouping of Chemical Elements. 



Elements. 



Atomic 

 Weights. 



Group 

 Position. 



Calculated 

 At. Wt. 



Difference. 



Group X. 



Magnesium .. 



Zinc 



Cadmium 



Gadolinium .. 

 Mercury 



Group XL 



Aluminium .. 



Gallium 



Indium 



Terbium 



Thallium 



Group XII^ 



Silicon 



Germanium . . 



Tin 



Erbium 



Lead 



Mean position, 9*82. 



Mg 



Zn 



Cd 



Gd 



Hg 



24-36 



65-40 

 1 12*40 

 156*00 



2O0'^O 



9-8 9 



10-94 

 968 

 979 



24*19 



65-22 

 109-09 



156-35 

 200-38 



+ 0-17 

 + 0-18 

 + 3"3 I 



-o'3S 



-0*08 



Mean position, 11*34. 



Al 

 Ga 

 In 

 Tb 

 Tl 



27*10 



70-00 



114 00 



i6o'oo 



204*10 



11-41 

 11*50 

 11*47 

 n*i8 

 1 1*14 



2696 



69-55 

 1 1360 



160*43 



204-66 



+ 0*14 



+ o-45 

 + 0-40 



-°"43 

 -0-56 



Mean (first) position, 12*21. 



Si 



Ge 



Sn 



Er 



Pb 



28*40 



12-09 



72-50 



12-38 



119-00 



13-12 



i66 - oo 



T 3'43 



206-90 



12-14 



28-60 



72-01 



Il6'22 



162-79 

 207-09 



+ 0-49 

 + 2*78 

 + 3-21 

 — 0*19 



