Successive ionization energy for cu²+

Here's what I get  

Explanation:

The ionization energy (I) is the energy required to remove an electron from an atom in the gaseous phase.

You can remove electrons in succession and measure the energies required as I₁, I₂, I₃, etc.

Thus, the removal of two electrons from Cu gives you Cu²⁺.

I found the ionization energies of Cu and used them to create those of Cu²⁺ (see table and graph below).

The electron configuration of Cu²⁺ is

Cu²⁺: 1s² 2s²2p⁶ 3s²3p⁶ 3d⁹

You can remove the nine 3d electrons and then there is a sudden jump from I₉ to I₁₀ as you break into the filled [Ar] configuration.

Similarly, there is big jump from I₁₇ to I₁₈ as you break into the filled [Ne] configuration.

just did the assignment and the answer was #1 +2 n