Question

which model is the most likely to result in ionization?
$h \
ightarrow h^+ + e^-$

Explanation:

Ionization requires enough energy to completely remove an electron from an atom. UV radiation has higher energy than visible light. The farther an electron is from the nucleus, the less energy is needed to remove it. The third model shows a UV photon interacting with an electron in the outermost (highest energy) orbital, so this combination of high-energy radiation and a loosely held electron is most likely to cause ionization.

Answer:

The rightmost model (UV radiation interacting with the electron in the outermost orbital)