The two exceptions
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The two exceptions
Can someone elaborate on why Cr and Cu are exceptions in the periodic electron configuration trend? Why is Cr 3d54s1 and Cu is 3d104s1, rather than having a full s orbital?
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Re: The two exceptions
There is stability in the symmetry of having all the d orbitals half full or fully full, and this stability leads to a lower energy when the d orbital is half full or fully full than the s-orbital being full, so electrons move to the d orbital because lower energy is preferable.
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Re: The two exceptions
Hi,
I think what the professor said in class was that it is because it is more stable for Cr to have an electron distribution with one unpaired electron in each of the d states. And the same thing with Cu.
I think what the professor said in class was that it is because it is more stable for Cr to have an electron distribution with one unpaired electron in each of the d states. And the same thing with Cu.
Re: The two exceptions
It is more stable to fill the 3d orbital. When it does so, the 3d orbital will drop in energy level (below 4s1). This is why we write Cu as [Ar] 3d10 4s1 rather than [Ar] 4s1 3d10.
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Re: The two exceptions
Half full d^5 and full d^10 subshells have lower energy, so it's more stable to fill those first.
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Re: The two exceptions
Hi! I believe these exceptions are due to the fact that it is more stable for the Cr and Cu atoms to exist with either a half or a full d orbital. I believe this is because that they are more stable when they are symmetric.
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Re: The two exceptions
Does that mean the elements in those two groups under Cr and Cu also follow this exception pattern for electron configuration?
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