Consider a hypothetical single$-$electron Bohr atom for which an electron in the nn $=1$ shell has a total energy of $-81\mathrm{.}0$ eVeV while one in the nn $=3$ shell has a total energy of $-9\mathrm{.}00$ eVeV. Which statements about this atom are correct?

Check all that apply.

If an electron makes a transition from the nn $=3$ to the nn $=1$ shell, it must absorb $72\mathrm{.}0$ eVeV of energy.If an electron makes a transition from the nn $=3$ to the nn $=1$ shell, it will give up $72\mathrm{.}0$ eVeV of energy.It takes $90\mathrm{.}0$ eVeV to move an electron from the nn $=1$ to the nn $=3$ shell.The energy needed to ionize the atom is $90\mathrm{.}0$ eVeV.