Why is the following situation impossible? In the Bohr model of the hydrogen atom, an electron moves in a circular orbit about a proton. The model states that the electron can exist only in certain allowed orbits around the proton: those whose radius $r$ satisfies $r=n^{2}(0.0529 \mathrm{nm}),$ where $n=1,2$ $3, \ldots$ For one of the possible allowed states of the atom, the electric potential energy of the system is $-13.6 \mathrm{eV}$.