Table 603 (a) (continued) 493 



ELECTRONS, PROTONS, ATOMIC STRUCTURE 



exceptions that of increasing atomic weights, and these exceptions are less anomalous 

 for the X-ray series than for the atomic-weight series. It seems plausible that there are 

 92 elements (from H to U) built up by the addition of some electrical element. Moseley 

 assigned successive integers to this series (see Table 508) known now as atomic numbers. 

 Moseley's discovery may be expressed in the form 



, h /„ 2 = Ei/E s or X 2 /X, = £i7£ 2 2 



where £ is the nuclear charge and X the wave length. Substituting for the highest fre- 

 quency line of W, X 2 = 0.167 X io~ 8 cm (Hull), £ 2 = 74 = iVw, and £1 = 1, then \i= 

 highest possible frequency by element which has one -f- electron ; \t = 91. 4mti. Now the H 

 ultra-violet series highest frequency line = 9i.2mAi (Lyman) ; i. e., this ultra-violet line of 

 H is nothing but its K X-ray line. Similarly, it seems equally certain that the ordinary 

 Balmer series of H (head at 3651x1/1) is its L X-ray series and Paschen^s infra-red series 

 its M X-ray series. 



The application of Newton's law to Moseley's law leads to E1/E2 = a 2 /ai, where the a's 

 are the radii of the inmost — electronic orbits, i. e., the radii of these orbits are inversely 

 proportional to the central charges or atomic numbers. 



There are other negative electrons on the nucleus with corresponding -f- charges to make 

 the atom neutral electrically. The negative nuclear charges may serve to hold the positive 

 ones together. He, atomic no. = 2, has two free + charges, on nucleus ; the nucleus has 

 4 + protons held together by 2 — electrons with 2 — electrons outside nucleus. H has 

 one + proton and one — electron. 



If the — electron is designated as e (charge — 1, mass negligible) and the + proton as p 

 (charge -f- I, mass 1 except in H) then the formula for the nucleus of any element from 

 He to U may be written as (p2e)n(pe)n where N is the atomic number and n has values 

 from o to 54. If 11 be taken as — 1, then H may be included. (Masson, Philos. Mag., 41, 

 1921.) If brackets are used to designate the nucleus then the complete element becomes 

 [(p2c)n(pe)n]eN. In the formation of ions only the part exterior to the brackets is affected. 

 For the o-transformation (emission of -f charged He nucleus) 2(/> 2 r) = (p2e)tf, the 

 subchemical equation may be written [(p2e)n(pe)n]eN = [(/> 2 e).v — 2(pe)n]e* + (fceW 

 (He nucleus); the new elements upon discharge of its — charge becomes [(p%e)s — 

 2(pe)n1eN — 2 showing the characteristic a-ray change with the atomic weight lowered 

 by 2 and the mass by 4. The /3-ray 2(pe) = (p2e) + e/ gives the equation 



[(p2c) x (pe) n ]c N = [(M)v+ i(pe)n-2 + cf 



mass unchanged and forms the singly — charged ion of an isobar. 



From the emission of nuclear a particles, 2(p 2 e) = p^e?, it seems probable that the nuclei 

 are compounds of He and I nuclei. By the bombardment of the nuclei of atoms up to 

 atomic number 40 with o particles Rutherford has obtained H but only where H and He 

 nuclei should both occur in the nucleus (Bo, N, Fl, Na, Al, P, see Table 638), Harkins has 



Smithsonian Tables 



