# stability of Cu(II), Cu(I) and Zn(II) ion

I would like to ask about the stability of $$\ce{Cu^{2+}}$$ and $$\ce{Cu^{+}}$$ and also $$\ce{Cu^{2+}}$$.

$$\ce{Cu^{2+}}$$ has a configuration of $$(3\mathrm{d})^9$$ but $$\ce{Cu^{+}}$$ has a configuration of $$(3\mathrm{d})^{10}$$. Why does $$\ce{Cu^{2+}}$$ are more stable and more common than $$\ce{Cu^{+}}$$. I am thinking of LFSE but I am not sure is it the correct way of thinking.

If $$\ce{Cu^{2+}}$$ $$(3\mathrm{d})^9$$ is more stable than $$\ce{Cu^{+}}$$ $$(3\mathrm{d})^{10}$$, then why we cannot see a $$\ce{Zn^{3+}}$$ where it is also $$(3\mathrm{d})^9$$?

• Notice the difference between meaning of M(II) and M(2+). The former is the metal atom with oxidation number +II, the latter the true ion with the charge +2e. So better to say Cu(2+) than Cu(II) ion. M(II) may part of covalent molecules, can have charge ligands etc. Feb 11, 2022 at 7:32
• Useful links for text and formula formatting (not to be applied to titles): Notation basics , Formatting of math/chem expressions and upright vs italic ----- For more, see Math SE MathJax tutorial. Feb 11, 2022 at 7:33
• Does this answer your question? Why Cu+ is unstable in aqueous medium? Feb 11, 2022 at 7:43
• @Poutnik u r right. I am a new user and I dont know how to type M(2+) neatly sorry for that I will change it after reading that passage Feb 11, 2022 at 8:00
• The link given by Nilay Ghosh 5 hours ago does not yield an answer. It says simply that hydrated $\ce{Cu^{2+}}$ is more stable, because it is more charged than $\ce{Cu+}$, so that it attracts more strongly the water molecules. If this was the reason, it could be applied to the case of the hydrated zinc atom, which should be more stable at the oxidation number +III. And of course,$\ce{Zn^{+3}}$ does not exist Feb 11, 2022 at 13:33

• But why the second ionization of $Cu$ is $1958 kJ/mol$ while 3rd ionization of $Zn$ is $3833 kJ/mol$? It seems that the value is unusually large. Both of the ionization involves removing an electron in $3d$ subshell turning it from $3d^{10}$ to $3d^9$. Since Zn has 1 more nuclear charge, it is expected to have a slightly larger value. But in real case, it is almost a double. Feb 11, 2022 at 15:30