﻿of 
  Atoms 
  and 
  Molecules, 
  191 
  

  

  It 
  is 
  seen 
  that 
  the 
  lines 
  discussed 
  by 
  Nicholson 
  are 
  given 
  

   "by 
  the 
  above 
  formula 
  if 
  we 
  put 
  r 
  2 
  = 
  G. 
  The 
  lines 
  in 
  question 
  

   correspond 
  to 
  r 
  1 
  =10,13, 
  and 
  14 
  ; 
  if 
  we 
  for 
  t 
  2 
  = 
  6 
  put 
  ^ 
  = 
  9, 
  12 
  

   and 
  15, 
  we 
  get 
  lines 
  coinciding 
  with 
  lines 
  of 
  the 
  ordinary 
  

   Balmer-spectrum 
  of 
  hydrogen. 
  If 
  we 
  in 
  the 
  above 
  formula 
  

   put 
  t 
  = 
  1, 
  2, 
  and 
  3, 
  we 
  get 
  series 
  of 
  lines 
  in 
  the 
  ultra-violet. 
  

   If 
  we 
  put 
  To 
  = 
  l 
  we 
  get 
  only 
  a 
  single 
  line 
  in 
  visible 
  spectrum, 
  

   viz.: 
  for 
  ^ 
  = 
  5 
  which 
  gives 
  v 
  = 
  b*'662. 
  10 
  14 
  , 
  or 
  a 
  wave-length 
  

   A 
  = 
  1503 
  . 
  10~ 
  s 
  cm. 
  closely 
  coinciding 
  with 
  the 
  wave-length 
  

   4501 
  . 
  10" 
  s 
  cm. 
  of 
  one 
  of 
  the 
  lines 
  of 
  unknown 
  origin 
  in 
  the 
  

   table 
  quoted 
  by 
  Nicholson. 
  In 
  this 
  table, 
  however, 
  no 
  lines 
  

   occur 
  corresponding 
  to 
  t 
  2 
  = 
  5. 
  

  

  For 
  the 
  permanent 
  state 
  of 
  a 
  lithium 
  atom 
  with 
  two 
  

   positive 
  charges 
  we 
  get 
  a 
  configuration 
  

  

  3(1) 
  a 
  = 
  ia 
  , 
  o)=9&) 
  , 
  W 
  = 
  9W 
  . 
  

  

  The 
  probability 
  of 
  a 
  permanent 
  configuration 
  in 
  which 
  

   two 
  electrons 
  move 
  in 
  different 
  orbits 
  around 
  each 
  other 
  

   must 
  for 
  lithium 
  be 
  considered 
  still 
  less 
  probable 
  than 
  for 
  

   helium, 
  as 
  the 
  ratio 
  between 
  the 
  radii 
  of 
  the 
  orbits 
  would 
  be 
  

   still 
  nearer 
  to 
  unity. 
  For 
  a 
  lithium 
  atom 
  with 
  a 
  single 
  

   positive 
  charge 
  we 
  shall, 
  therefore, 
  adopt 
  the 
  configuration: 
  

  

  3(2) 
  a 
  = 
  0*361d 
  , 
  ft) 
  = 
  7'56o? 
  . 
  AV 
  = 
  15\13W 
  . 
  

  

  Since 
  W[3(2)]— 
  W[3(i)]=6*13 
  W 
  , 
  we 
  see 
  that 
  the 
  

   first 
  two 
  electrons 
  in 
  a 
  lithium 
  atom 
  are 
  very 
  strongly 
  bound 
  

   compared 
  with 
  the 
  electron 
  in 
  a 
  hydrogen 
  atom; 
  they 
  are 
  

   still 
  more 
  rigidly 
  bound 
  than 
  the 
  electrons 
  in 
  a 
  helium 
  

   atom. 
  

  

  From 
  a 
  consideration 
  of 
  the 
  chemical 
  properties 
  we 
  should 
  

   ■expect 
  the 
  following 
  configuration 
  for 
  the 
  electrons 
  in 
  a 
  

   neutral 
  lithium 
  atom 
  : 
  

  

  3 
  ( 
  2,l) 
  »i=0;362 
  «. 
  »i 
  = 
  7-65 
  o> 
  W 
  =1602W». 
  

   ao 
  = 
  ribJa,j 
  a>2=U 
  , 
  71ow 
  fl 
  

  

  This 
  configuration 
  may 
  be 
  considered 
  as 
  highly 
  probable 
  

   also 
  from 
  a 
  dynamical 
  point 
  of 
  view. 
  The 
  deviation 
  of 
  the 
  

   outermost 
  electron 
  from 
  a 
  circular 
  orbit 
  will 
  be 
  very 
  small, 
  

   partly 
  on 
  account 
  of 
  the 
  great 
  values 
  of 
  the 
  ratio 
  between 
  

   the 
  radii, 
  and 
  of 
  the 
  ratio 
  between 
  the 
  frequencies 
  of 
  the 
  

   orbits 
  of 
  the 
  inner 
  and 
  outer 
  electrons, 
  partly 
  also 
  on 
  account 
  

   of 
  the 
  symmetrical 
  arrangement 
  of 
  the 
  inner 
  electrons. 
  

   Accordingly, 
  it 
  appears 
  probable 
  that 
  the 
  three 
  electrons 
  

  

  