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## Homework Statement

The equation E

_{n}=-Z

^{2}R

_{H}/n

^{2}gives the energy (according to the Bohr model) of the energy levels available to an electron in any hydrogen-like atom. Calculate the second ionization energy of He(in J). The second ionization energy of He is the ionization energy of He

^{+}.

## Homework Equations

E

_{n}=-Z

^{2}R

_{H}/n

^{2}where R

_{H}=2.178x10

^{-18}J

Z=2

n=?

## The Attempt at a Solution

I don't understand which value I am supposed to use for n. When I look up the second ionization energy of He I find that the answer is 54.4 eV or 8.712x10

^{-18}J, which is the answer I get when I input n=1 into the above equation. But it's asking for the second ionization energy of He, so why would I use n=1?