﻿318 
  Dr. 
  L. 
  Vegard 
  on 
  the 
  X-Ray 
  Spectra 
  

  

  1 
  he 
  Constitution 
  of 
  the 
  Elements 
  based 
  on 
  the 
  

   X-ray 
  Spectra. 
  

  

  The 
  theory 
  of 
  the 
  X-ray 
  spectra 
  involves 
  the 
  determination 
  

   o£ 
  the 
  electronic 
  systems 
  next 
  to 
  the 
  nucleus, 
  and 
  may 
  give 
  

   us 
  valuable 
  information 
  as 
  to 
  the 
  way 
  in 
  which 
  the 
  electrons 
  

   round 
  the 
  nucleus 
  are 
  grouped 
  together. 
  

  

  The 
  previous 
  investigation 
  has 
  shown 
  that 
  the 
  K-series 
  

   should 
  be 
  attached 
  to 
  a 
  ring 
  with 
  quant 
  number 
  1 
  next 
  

   to 
  the 
  nucleus 
  and 
  containing 
  3 
  electrons. 
  The 
  L-series 
  

   should 
  be 
  due 
  to 
  two 
  rings 
  with 
  quant 
  numbers 
  2 
  and 
  con- 
  

   sisting 
  of 
  7 
  and 
  8 
  electrons. 
  The 
  M-series 
  should 
  probably 
  

   have 
  rings 
  with 
  a 
  quant 
  number 
  3 
  and 
  9-10 
  electrons. 
  

  

  I£ 
  this 
  theory 
  is 
  right, 
  it 
  would 
  mean 
  that 
  if 
  a 
  ring 
  is 
  

   formed 
  for 
  lower 
  atomic 
  numbers 
  the 
  same 
  ring 
  is 
  kept 
  

   throughout 
  the 
  whole 
  system 
  of 
  elements. 
  Indeed 
  I 
  think 
  

   that 
  this 
  is 
  to 
  be 
  considered 
  as 
  a 
  necessary 
  consequence 
  to 
  

   be 
  derived 
  from 
  the 
  simple 
  laws 
  governing 
  the 
  X-ray 
  

   spectra, 
  and 
  is 
  independent 
  of 
  any 
  special 
  theory 
  which 
  we 
  

   propose 
  to 
  explain 
  the 
  frequencies 
  and 
  the 
  type 
  of 
  the 
  

   spectra. 
  For 
  a 
  change 
  in 
  the 
  number 
  of 
  electrons 
  in 
  the 
  

   K-ring, 
  say, 
  would 
  necessarily 
  involve 
  a 
  discontinuity 
  in 
  

   the 
  formula 
  expressing 
  the 
  relation 
  between 
  frequency 
  and 
  

   atomic 
  number. 
  

  

  Now 
  it 
  might 
  be 
  legitimate 
  as 
  an 
  hypothesis 
  to 
  take 
  this 
  

   rule 
  as 
  a 
  fundamental 
  property 
  of 
  the 
  atomic 
  structure, 
  and 
  

   quite 
  general 
  to 
  assume 
  that 
  a 
  system 
  of 
  electrons 
  once 
  

   formed 
  is 
  kept 
  also 
  for 
  elements 
  of 
  higher 
  atomic 
  numbers. 
  

   There 
  is 
  no 
  reason 
  why 
  this 
  rule 
  should 
  cease 
  to 
  hold 
  because 
  

   we 
  pass 
  to 
  lower 
  frequencies. 
  

  

  Now 
  if 
  we 
  would 
  further 
  build 
  on 
  the 
  result 
  of 
  our 
  present 
  

   theory 
  as 
  to 
  the 
  number 
  of 
  electrons 
  in 
  the 
  K- 
  and 
  L-rings, 
  

   we 
  should 
  get 
  a 
  quite 
  definite 
  system 
  for 
  the 
  first 
  eighteen 
  

   elements, 
  and 
  from 
  this 
  start 
  we 
  should 
  be 
  able 
  to 
  see 
  how 
  

   the 
  electrons 
  are 
  arranged 
  in 
  a 
  series 
  of 
  elements 
  forming 
  

   one 
  period 
  in 
  the 
  periodic 
  system. 
  If 
  we 
  have 
  proceeded 
  so 
  

   far, 
  we 
  can 
  get 
  further 
  by 
  the 
  assumption 
  that 
  elements 
  of 
  

   the 
  same 
  family, 
  such 
  as 
  Li, 
  Na, 
  and 
  K 
  say, 
  must 
  have 
  the 
  

   same 
  number 
  of 
  electrons 
  in 
  the 
  outer 
  ring. 
  I 
  think 
  this 
  is 
  

   an 
  assumption 
  which 
  is 
  very 
  well 
  founded, 
  because 
  the 
  

   chemical 
  properties 
  must 
  be 
  mainly 
  determined 
  by 
  the 
  

   outer 
  electrons, 
  and 
  the 
  assumption 
  is 
  independent 
  of 
  any 
  

   other 
  special 
  hypothesis 
  with 
  regard 
  to 
  the 
  grouping 
  of 
  

   the 
  electrons. 
  

  

  Proceeding 
  in 
  this 
  way, 
  we 
  assume 
  in 
  accordance 
  with 
  

   Bohr 
  that 
  the 
  strongest 
  electropositive 
  elements 
  have 
  

  

  