Quantum energy level, calcualting total energy

[lagwagon555]

Homework Statement

The element N has 7 electrons and 7 protons in the atom. An ion of N has all the electrons removed except 1, so it resembles a hydrogen atom with a nuclear charge of +7 e.

E1(Hydrogen)= -13.6eV, r1(Hydrogen)= 5.29x10^-11m.
k = 8.99x10^9 e = 1.6x10^-19

What is the total energy (in eV) of the lowest energy state available to the ion?

Homework Equations

E = -((k*e^2)/(2r))

The Attempt at a Solution

It's been driving me insane! I've put every single combination of variables into the equation, and nothing is coming out correctly. They're all in order of magnitudes wrong, so I think I might be using the wrong constants/variables, or even the wrong equation. Can anyone point me in the right direction, as to what I should be putting where? Thanks!

 

[w3390]

Use the equation En=-Z^2*(E0/n^2), where n is the energy level, Z is the number of protons, and E0 is 13.6 eV. I think this will give you the correct answer.

 

[lagwagon555]

Absolutely brilliant. I haven't seen that equation yet, so I'll have to look it up to understand it, but it sure as heck works! Thanks for your time, hugely appreciated.