Energy required to strip final electron

[BobMcPhysics]

Homework Statement

Find the energy in electron-volts required to remove the remaining electron from a doubly ionized lithium (Li2+) atom.

Homework Equations

En=-z^2/n^2

The Attempt at a Solution

I thought z was 3 for lithium, that doesn't work. I thought since there was only one remaining electron you could treat it like Hydrogen and use z (or E1) = -13.6 eV but that's not right either. Clearly the n in the denominator is 1 from above.

I'm lost!

 

[Redbelly98]

Welcome to Physics Forums.

En=-z^2/n^2

You'd better double-check that formula, especially the Z part of it.

I'm assuming you know how to convert the answer to eV, but post back if that is a problem.

Possibly helpful link:

http://en.wikipedia.org/wiki/Hydrogen-like_atom#Mathematical_characterization