Energy required to fully ionize Uranium

[doppeled]

1. What is the maximum wavelength of light required to fully ionised Uranium to U92+, i.e.
strip it of all electrons and leaving a bare nucleus? For simplicity, only consider direct
ionisation and neglect non-linear effects.




Attempt at solution

Ok, so the electron structure of the atom is 2,8,18,32,21,9,2. Ionization will be the energy required to remove an electron that is the least tightly bound to the atom. In order to completely ionize the atom do I calculate the energy required to ionize each electron at their respective energy levels? I am a bit confused as to how to tackle the problem.
Thanks

 

[DrClaude]

What is the maximum wavelength of light required to fully ionised Uranium to U92+, i.e.
strip it of all electrons and leaving a bare nucleus? For simplicity, only consider direct
ionisation and neglect non-linear effects.

[...]

In order to completely ionize the atom do I calculate the energy required to ionize each electron at their respective energy levels?

I think this is where your confusion is coming from: these two statements of the problem are different.

You are not asked the total energy to ionize the atom, but the highest energy photon needed. Consider that one photon removes one electron, what electron will be the hardest to remove?

 

[doppeled]

Ah yes, I think I understand now. So just a matter of calculating the energy required to remove an electron closest to the nucleus, which is in the ground state.

Thank you for your help.

 

[DrClaude]

Ah yes, I think I understand now. So just a matter of calculating the energy required to remove an electron closest to the nucleus, which is in the ground state.

Just to make clear, it will be the energy needed to remove the last electron.

 

[doppeled]

Yes so during ionization the outermost, least bound electrons will be removed first, and so by calculating wavelength required to remove the last electron we have a sufficient energy to completely ionize.