Hackh — Modification of the Periodic Table. J-95 



more affected by the period relation than the group rela- 

 tion. Thus we find that CuCl and AgCl, while still stable, 

 are less soluble and ionized, while AuCl is unstable and 

 hydrolyzes with water forming Au and AuCL, this latter 

 chloride being more stable and closely related to PtCl 3 , as 

 should be expected from the rule given above. 



To give further illustrations of this rule of "vertical" 

 resemblance in the upper half, and "horizontal" resem- 

 blance in the lower half of the table, is unnecessary ; an 



metallic 



non-metallic 



32. Germanium 

 Ge 



5.496 



33. Arsenic 

 Asi Aso Aso As 



erst 

 5.74 



gray brwn|yllw. 



3.7 



2.21 



34. Selenium 

 Se^ Seg Se x 



matl lmncl 

 4.8 4.46 



amph. 

 4.26 



35. Br 



3.187 



14. Silicon 

 Sii Si x 



erst J amph. 



2.49 2.35 



15. Phosphorus 

 p 2 p 8 ^4 



violet 

 2.34 



red 

 2.16 



white 

 1.83 



16. Sulphur 



$Q Sq S3 



octr lmncl L amph 



2.07|1.95| 1.92 



17. CI 



liqu. 

 1.33 



6. Carbon 



Dmnd 

 3.53 



!$£?$ 



7 . Ni trogen 



8. Oxygen 



0.80 



1 li^u 

 1.134 



9.F 



liqu. 

 0.988 



erst.- cri'stallinic amph.- amorphous 

 metl.- metallic mncl.-monoclinic 



liqu.- liquid 



1 .Hydrogen 

 liqu. 



Si 



metl 

 0.62 



0.061 



Table V. The allotropic forms of some nonmetals, showing the position 

 toward the metallic side. 



examination will make this self-evident. It should be 

 pointed out, however, that by the separation of the ele- 

 ments into their A and B groups, the periodicity of their 

 properties is more clearly exhibited and one can grasp 

 the increasing or decreasing tendencies of these proper- 

 ties rn a more convenient and shorter way. A very good 

 illustration is furnished by Table IV, showing the specific 

 gravity of the elements. The arrows indicate the 

 increasing density, which follows the arrows with the 

 exception of some elements of the first period, in a strik- 

 ing manner. It is well known that in a given group of 

 elements the metallic character increases with increasing 



