[er4444]

An energetically excited H atom has its electron in a 5f subshell. The electron drops down to the 3d subshell, releasing a photon in the process.
d. The hydrogen atom now has a single electron in the 3d subshell. What is the energy in kJ/mol required to remove this electron and form the H^+ ion.

I decided to use the Rydberg equation to calculate the energy of a photon that results in n=3 changing to n=1. I have no idea how to find what energy we need to take the ion out completely, or if I even needed to use the rydberg there. The only equation we have learned about the minimum to get an electron out is:

KE=hv-W=hv-hv_0

KE=kinetic energy of ejected electron
h=plancks constant
v=frequency
W=work
v_0=threshold frequency for electron to eject