The Energy of the Nth Level in a One-Electron Atom

Multiple Choice

The energy of the nth level in a one-electron atom is . Consider a beryllium ion with all but one of its electrons removed a beryllium atom normally has four electrons) . What is the energy of the electron when it is in the third-lowest energy state?

A) -24 eV
B) -7.6 eV
C) -1.5 eV
D) 24 eV
E) 7.6 eV