Chromium can have two possible configurations: (4s)^2(3d)^4 and (4s)^1(3d)^5. Th
ID: 807453 • Letter: C
Question
Chromium can have two possible configurations: (4s)^2(3d)^4 and (4s)^1(3d)^5. The latter configuration is favored due to the added stability of the half filled d-shell. a) Determine the GROUND STATE TERM SYMBOLS for both configurations. Hint: You don't have to find all of the terms, just the lowest energy one. Remember Hund's rules. Show all possible J-values for both configurations. b) Do Hund's rules help rationalize why the (4s)^1 (3d)^5 configuration is lower than the (4s)^2 (3d)^4 configuration? Why or why not?Explanation / Answer
For a given term, in an atom with outermost subshell half-filled or less, the level with the lowest value of the total angular momentum quantum number J is the ground state
(a) ground state term symbol for two states:
for 4s2 3d4
L = 2 s= 4/2 2S + 1 = 5
number of possible J value = L + s to L-s
5D45D3 5D2 5D1 5D0 (ground state)
for 4s1 3d5
L = 0 s = 6/2, 2S + 1 = 7 J= L+ s to L-s
only one state possible 7S3
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According to Hund's rule the state which has the maximum spin multiplicity (2s + 1) will be the ground state.
between 5D0 and 7S3 , the latter has higher spin multiplicity. Hence 4s1 3d5 will be the ground state