I have an assignment to 'Research ionization energy levels and come up with 3 real world applications' and was told you look up lasers, plasma arcs and neon lights. Hours later, (lol) I'm still having a little trouble. Is there any way someone can explain the connection between ionization energy levels and lasers, plasma arcs and neon lights?

2 answers

Bob Pursley gave you that very good answer. I'll get you started with neon lights.
Neon lights (that's the common name but they may contain other gases than neon) are tubes, usually of glass, with a connection at each end and a voltage is applied to the electrodes. Electrons stream from the negative electrode to the positive electrode. In the process of moving from one electrode to the other they knock electrons in the enclosed gas to higher energy levels. In many cases the electron is completely removed from the gas atom. (That's ionization.) When the electrons (either the original or a different one) return to the atom, energy is emitted and much of that is in the visible region of light. We see the emitted light in different colors depending upon the gas inside the glass tube. Some neon signs have a dye coating inside the glass and that dye fluoresces to emit different colors. Most of what I've written explains neon signs but you will note about half way through the gas atom is ionized when an electron is completely removed from the atom. That's where you come in.
Ionization is when an electron is removed from an atom and ionization energy is the energy required to do this. "Electrons stream from the negative electrode to the positive electrode. In the process of moving from one electrode to the other they knock electrons in the enclosed gas to higher energy levels. In many cases the electron is completely removed from the gas atom." I'm completely unsure of this but does the color of the neon sign depend on how high the ionization energy level needs to be to remove the electron from the gas atom?