THK PRESIIJEXT S ADDRESS 2"/ 



ring, the number which can be placed within is Hmited by two 

 extremes. The most suggestive case of this kind is that with 

 20 electrons in the outer ring. The total number of electrons 

 with such an outer ring can never be less than 59 and can not 

 exceed 67. This might be supposed to correspond to a group of 

 nine elements of the periodic system from helium to neon or from 

 neon to argon. The arrangement with 59 electrons, if it lost one. 

 would be compelled to rearrange to a form having only 19 elec- 

 trons in the outer ring, but owing to the positive charge acquired 

 by the loss of the electron, it would immediately acquire another 

 and go back to its original form. Such an element would have a 

 valence of o for a positive charge, and Professor Thomson sug- 

 gests that this wottld correspond to such an element as helium or 

 neon. But he goes on to say that the element would have a 

 valency of 8 for a negative charge, which does not. of course, 

 correspond to the properties of the zero group. A group of 60 

 electrons might lose one electron and acquire a permanent positive 

 charge of one valence, which would correspond to such an element 

 as lithium or sodium. It ought, however, to be capable of gaining 

 7 electrons : that is. it should have a valency of seven for a nega- 

 tive charge. Here, again, the facts do not correspond to the 

 theory. It seems evident that the theory needs to be supplemented 

 by some explanation why electropositive elements lose electrons 

 btit do not readily take them up. while it would seem that the 

 electronegative elements can do both. The facts seem to he con- 

 nected wnth the properties of metals as conductors and of non- 

 metals as non-conductors. 



Lorenz in his explanation of the Zeen^.an effect seems to assume 

 that the electrons revolve around a nucleus of matter having a 

 po-iiive charge. It seems possible that the idea of Lorenz is true 

 for metals, that of Thomson for non-metals. 



Whichever theory is accepted, the notion that atoms may 

 acquire positive or negative charges by the loss or gain of an 

 electron and that th§ charged atom may then attract another atom 

 bearing a charge of the opposite sign seems likely to be a fruitful 

 one. I will give an illustration of possible application to well- 

 known facts. An atom of nitrogen may receive four electrons 

 from four hydrogen atoms if at the same time it gives one to the 

 oxygen atom of a hydroxy 1 group. But the hydroxyl group is 

 loosely held by the nitrogen atom with its four electrons and the 

 compound ionizes and reacts as though consfsting of ammonium 

 and hydroxyl. One atom of nitrogen may also give five electrons 

 to three oxygen atoms in forming nitric acid. Here the nitrogen 



