[potassium_carbonate]

Hello,
I am wondering something about copper and its electron configurations as an ion. I know that Cu has an irregular configuration, [Ar]4s¹ 3d¹⁰, and I also know its ion configurations. What I am wondering is why. I know why the configs are irregular. What I'm really looking for here is why a Copper II ion is more common and more stable, when it would seem that the Copper 1 ion is, with its [Ar]3d¹⁰ configuration. I've tried looking everywhere, but nothing helpful can be found. I've discussed this with my chemistry teacher, who is also wondering this. Please don't give me the full answer. I would like some guidance on where to look to try and find this out on my own (as much as I can). Thanks so much!

[mikasaur]

It looks like the answer to this question is fairly complicated. A little bit of Googling brought me to the Jahn-Teller effect: https://en.wikipedia.org/wiki/Jahn%E2%80%93Teller_effect

[Corribus]

You may find this thread useful.

http://www.chemicalforums.com/index.php?topic=3055.0

[potassium_carbonate]

Thanks so much everyone! It is much appreciated.

[Enthalpy]

I don't think a complete d¹⁰ alone is especially favourable. If you compare the elements and their filling, the noble gases (except helium) fill up to p⁶, never up to d¹⁰. In the first two series of transition elements, d competes with s - sometimes one is full, sometimes the other, or none. But beginning with Zn, 3d¹⁰4s² doesn't change any more, and beginning with Cd, 4d¹⁰5s² neither, so you can conceive 3d4s or 4d5s as one single shell with unobvious filling - not even a favourable shell since Zn and Cd are reactive.