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Homework Help: Electronic Configuration of Fe+

  1. Nov 24, 2011 #1


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    Previously I had been asked the configuration for Fe+ as an ordinary question from Periodic Table. I know Fe2+ and Fe3+ but I have no idea for Fe+

    I know the configuration of Fe : [Ar]4s23d6

    So I accordingly wrote Fe+ as [Ar]4s13d6

    But they say that Fe+ is [Ar]4s03d7

    I just want to confirm that is this electronic configuration correct?
  2. jcsd
  3. Nov 25, 2011 #2
    Yes what they say is correct thats because in a chemical enviroment the d orbital is lower in energy than the s so is filled before the s orbital( I'm not sure if you would have been taught this yet, i got taught it first year undergrad).
  4. Nov 25, 2011 #3


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    It doesn't want to be that easy. Blindly using this rule you will get d8s0 instead of d6s2 for the ground state of Fe(0), so it is obviously wrong in general.

    Unfortunately I don't know answer to the original question, other then "because that's the way it is" (assuming that's the way it is). When it comes to configurations there are rules of thumb that work in most cases, and there are exact calculations/measurements that sometimes falsify the rules. Once you know rule of thumb fails for a particular case you can make any kind of handwawy argument like "in this case low spin/high spin configuration is energetically favored", but IMHO it doesn't give you any more reliable tool to predict the configurations in other cases.
  5. Nov 25, 2011 #4
    I meant for ions , for isolated species(with no formal charge) then it does obey the normal rule
  6. Nov 25, 2011 #5


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    OK... This is the tricky one, but solved! :smile:
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