SOME FURTHER CONSIDERATIONS IN THE DEVELOP-" 



MENT OF THE ELECTRON CONCEPTION 



OF VALENCE. 



By K. GEORGE FALK. 

 (Read April 24, 19 14.) 



The electron conception of valence is based upon the view that 

 when two atoms combine, one becomes charged positively and the 

 other negatively. According to J. J. Thomson,^ the union of two 

 atoms is brought about by the transfer of a negatively charged cor- 

 puscle from one atom to the other; the atom losing the corpuscle 

 becoming charged positively, the one gaining the corpuscle, charged 

 negatively. In order to represent graphically the linkings between 

 atoms the lines or dots which represent the bonds ordinarily are 

 replaced by arrows in the electronic considerations, the head of the 

 arrow indicating the direction in which the corpuscle is assumed to 

 be transferred in the production of the chemical bond. 



In every discussion of valence, it is necessary to consider the 

 limitations of the problem. Valence is a number. The valence of 

 an atom shows the number of corpuscles or negative electrons 

 gained or lost by that atom in forming chemical bonds. In slightly 

 different terms, the valence of an atom shows the number of atoms 

 (or groups of atoms) held in combination by that atom when the 

 hydrogen atom as it exists in most of its compounds is taken as the 

 positive unit. Valence may be likened to the capacity factor in 

 energy considerations.- Like the capacity factor, it is denoted by a 

 definite number, and while this number may vary under different 

 conditions, a quantity or number of atoms (or combining weights) 

 held by an atom (or combining weight) of the element in question 

 is always meant. 



1 " The Corpuscular Theory of Matter," pp. 13S-9 (1907). 



2 Cf. S. L. Bigelow, "Theoretical and Physical Chemistry," p. 80 (1913). 



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