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    construct the molecular orbital energy level diagram for ClF.

    HELP!!!!!
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    for chlorine and fluorine?
    or Chlorine fluroide which doesnt exsist to the best of my knowledge. I suppose if you can have a CL2 molecule you could be subsistuting one of the chlorines for a fluroine. What exam board and level is this for?
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    (Original post by Speciez99)
    What exam board and level is this for?
    Just to emphasise, cos I'm thinking degree level here...?!
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    its definitely ClF - an interhalogen molecule.

    yep, its degree level.... even if anyone knows any sites i can look at?
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    Ah shucks, I wasn't hoping that wasn't the case... OK then, well, I guess it's good revision!!

    Which bit of it are you stuck on exactly? I'm not in chem mental mode at the moment so if you could spell out the question and the problem that'd help me think it through, and if I can help I will (although physical chemistry isn't my forte by a long road!!)
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    ok....i know that because fluorine is more electronegative than chlorine this means that fluorine's 2s orbital is the lowest in energy. However, i do not know which is the next lower in energy- fluorines's 2p orbitals, or chlorine's 3s orbital!...do you know what i mean by this? or have i confused you further?!
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    i'm thinking the order or the orbitals,starting with the lowest in energy, is:

    fluorine 2s
    chlorine 3s
    fluorine 2p
    chlorine 3p

    is that right?
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    Hi sorry wasn't online!

    Hmm. I have an orbital energies graph in front of me which helpfully doesn't show anything but fluorine 2s and 2p - however it looks to me like the fluorine 2p is highest in energy, followed by the 2s and then - at least this is implied by the graph - chlorine's 2p and 2s are considerably lower (off the scale on this graph which is why they're not shown). I think this does make sense if you think about it - chlorine is less electronegative overall but has a considerably higher nuclear charge than fluorine, so the electrons as close to the nucleus as 2s and 2p should be held more strongly and so at a lower energy than fluorine's. I think there's quite a gap though so I don't envy you for drawing the orbital diagram...!
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    thanks, i understand what your saying, but its the energy of the chlorine 3s and 3p orbitals relative to that of the fluorine 2s and 2p orbitals which is what i really need to know now in order to be able to draw the MO diagram. you don't happen to know how that would work do you?
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    Oh dammit, sorry, completely misread before! OK. According to the ever-lovely graph the order is as follows (lowest energy at the bottom, highest at the top):

    Cl 3p
    F 2p
    Cl 3s
    F 2s

    - so yeah, exactly what you surmised.

    Phew, sorry about that, must not be working on a full brain today!
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    thanx alot for your help, wish i had a graph like that to help me...you dont happen to know what the energy levels for the MOs look like do you? does it look something like the MO energy level diagram for CO?

    .....and is the order of the atomic orbitals for Cl and I the same as Cl and F:
    I 5p
    Cl 3p
    I 5s
    Cl 3s

    ....just wondering?
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    I should think the energy level diagram would be similar to that for CO... *hopes!*

    The graph only goes up to the 4th principal shell but it looks to me, from the patterns on here, as though your prediction may be right... But I really can't say for certain because the pattern isn't consistent so it's kinda hard to predict the shape of the 5s line. I think your suggestion's probably reasonable though. Sorry I can't be more helpful than that!
 
 
 

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