Atoms and Molecules. 891 



difference between carbon and the preceding atoms first 

 makes its appearance in that there are two connecting 

 electrons instead of a single one between the doublets con- 

 taining the positive individuals The connecting electrons 

 do not remain in the equatorial plane exactly, but are 

 staggered the one up and the next down alternating 

 all the way around. This feature is not shown in the 

 model. 



The oxygen atom is very similar to carbon, but differs in 

 being based upon a square of positive charges instead of 

 an equilateral triangle. There are also double connecting 

 electrons as in carbon. The mass is exactly 16, there 

 being no isotopes. 



The only remaining atom in the second row of the periodic 

 table is nitrogen. This differs materially from the ring form 

 of carbon and oxygen, and has an alpha particle at its exact 

 centre surrounded by a hexagon of single electrons, which 

 are supposed to be staggered alternately up and down out of 

 the equatorial plane. The circumference outside of this 

 hexagon contains two alpha particles and two hydrogen 

 atoms, and the whole figure has two planes of symmetry. 

 The mass is 3 x 4 = 12 plus 2 x 1*008 = 2-016, making a total 

 of 14*016, thus agreeing with remarkable accuracy with the 

 official weight of nitrogen, 14*01, which has been determined 

 with as much or more care than any other element. 



The next element, neon, has two isotopes at least, one of 

 mass 20 and the other 22. The form, Ne-No. 1 fig. 1, is 

 thought to be made by the addition of a helium atom in the 

 centre of the oxygen ring, the five alpha particles having a 

 mass 20. The isotope of this, 22, not shown in fig. 1, is 

 thought to consist of the same atom to which is added two 

 hydrogen atoms, one on either pole of the central helium 

 atom, thus making a pile of three coaxial atoms in the centre 

 of the oxygen ring, one helium atom and two hydrogen atoms. 



The next element, sodium, has no isotopes as yet found 

 and an exact weight of 23. It falls under Li in the periodic 

 table, and is thought to consist of the hexagon isotope of Li 

 of mass 7 within the oxygen ring of mass lb, thus making up 

 the total mass 23. 



This is as far as we shall attempt to go at the present time, 

 although considerable interest attaches to the elements imme- 

 diately following, Mg, Al, Si, P, S, and CI, to complete the 

 third row in the periodic table. Of these, Mg, Al, Si, and 

 CI are known to have isotopes. 



The work of Rutherford in the disintegration of nitrogen 

 and oxygen will immediately occur to the reader, because 



