Constitution and Stability of Atom Nuclei. 32 L 



additional evidence, but in a simpler form, that this is a 

 general relation, it may be stated that in all of the elements 

 investigated by the positive ray method, with the single 

 exception of nitrogen (and possibly xenon), the most abundant 

 isotope contains an even number of nuclear negative electrons. 

 This is shown in Table V. 



Table V. 

 The Number of Negative Electrons in the Nucleus of the Most 

 Abundant Isotope of Each Element thus far Investigated 

 by the Positive Ray Method *. 



Atomic Number (N) of Negative Electrons in the Nucleus.. 



Number. Element. Even number. Odd number. 



2 Helium 2 



5 Boron 6 



6 Carbon 6 



7 Nitrogen ... 7 



8 Oxygen 8 



9 Fluorine 10 



10 Neon 10 



12 Magnesium 12 



14 Silicon 14 



15 Phosphorus 16 



16 Sulphur 16 



17 Chlorine 18 



18 Argon 22 



33 Arsenic 42 



35 Bromine 44 



36 Krypton ... 48 



53 Iodine 74 



* While xenon and mercury have both been investigated by Aston, the 

 atomic weight of the most abundant isotope seems to be in doubt. All of the 

 atomic weights were determined by Aston, with the exception of that of 

 magnesium by Dempster. The chemically determined atomic weights when 

 interpreted in the light of the hydrogen-helium theory of the writer, indicate 

 that to the list of most abundant isotopes which contain an even number of 

 electrons may be added : 



Li,", Na x 23 , Al^, V 5 5 S Mn», Co., 59 , Ca„ 40 , Ti 4 48 , Cr/ 2 , and Fe 4 5u , 



all in the region of the light atoms, lliis may be considered as a prediction. 



It should be noted that in the one case, nitrogen, in which the number of 

 electrons is odd in the most abundant isotope, this isotope and the whole 

 element, since it consists of only one species, is quite rare, in spito of the fact 

 that its isotopic number is zero, which might be expected to give it a high 

 abundance if it were not that the nucleus belongs to Class IV. instead of to 

 Class I. It is probable that the rarity of neon is due to the fact that it ia not 

 held chemically and has a low molecular weight, so it has either escaped from 

 the earth's atmosphere, or was not carried with the smaller earth nucleus when 

 it was formed. 



Phil. Mag. S. 6. Vol. 42. No. 249. Sept. 1921. X 



