Question

find the frequency of light that strikes a stable hydrogen atom causes it just enough to a) excite b) ionize?

Answer 1

What is the formula for the energy levels of a single electron hydrogen atom? And what is the ionization energy of such an atom?

Once you know that, you can calculate the frequency of the photon using
\[ E = hf \]

Answer 2

Does this diagram look familiar?

Answer 3

In its ground state, the energy level of the electron of a hydrogen at has an energy level of -13.6 eV [electron volts]. This means that electron would need to receive at least that much energy to break feee of the atom. Think of it in an energy well.

Now, what are the other energy levels?

Answer 4

if you don't talk to me, it's hard to help you further.