Transition Metals

Why doesn't Zn form a Zn+ or Zn3+ ion?
Why does having a 3d10 4s0 configuration give Zn extra stability rather than a 3d9 4s0 configuration like Cu2+?


Edit
Why is Cu unable to form a Cu3+ ion as well, it can lose a d electron to form Cu2+ so why not one more?

Both copper(III) and copper(IV) are known ...

Oh right...But why is zinc most stable in the +2 oxidation state?

The 4s electrons are easily lost but not the 3d electrons as by Zn the 3d orbitals have significantly dropped in energy due to the increase in nuclear charge. It therefore takes too much energy to remove the 3rd electron by chemical means.

Zn has full d and s orbitals. Losing one s electron isn't favourable. It can however lose 2 from the s orbital since the s would be completely empty whilst the d still full. It won't lose 3 because once again it's not favourable to lose one electron from the d orbital.

Then why is a Cu2+ ion easily formed?

Because the 4s are easily lost! The 3d are still more difficult to remove but not quite as much. The Zn2+ d electrons are further stabilised by the full d shell giving the greatest exchange stabilisation.
The 2+ state is the most stable for the late transition metals and the 3+ is only stable for the earlier TM's because the 3d is stabilised as you move right across the series

But wouldn't Cu+ be more stable than Cu2+ because of the 3d10 4s0 arrangement giving the greatest exchange energy?

But the higher charge leads to stronger bonds, which make the ionisation energetically favourable.