Help with Chemistry!! Didnt know where else to post :(

We did a lab in our grade 11 chemistry class using spectrometers to see spectroms of various gases when 500 volts were passed through the gas discharge tube. There are a few questions and i dont know how to answer these ones. Please help!

First one
-->Hydrogen has only 1 electron. However its emission spectrum exhibits 4 visible lines. Can you explain??

Hints to the first question: Recall the aluminum bohr diagram(empty energy levels still exist). Electron in a particular energy level possesses a certain amount of energy. An electron can absorb additional energy from energy sources. Electrons hold on to extra energy for a short time (10^-6 seconds).

My second question.
Suggest reasons for neons many spectral lines and why they arent in the same locations as those from hydrogen.

my third question.
Mercury showed only a few visible spectral lines despite the fact that it posses 80 electrons. explain..

If you can even answer just one of these questions you'll be helping me alot.. Thank you in advance for any help!!

From what i remember and i don't remember much, the extra energy added to the electrons makes it jump to other orbits and when the energy is released again it will be emmitted at a frequency proportional to the energy, by a factor of plank's constant (E=hf) I suppose hydrogen will do that cause there's only 4 orbits to go, You can calculate the difference between the orbits and get the frequencies from there.

My guess is that the spectral lines are due to changes in the energy levels of electrons in the outer shell (using the Bohr plaentary model). The possible energy levels for the single hydrogen atom are filled by electrons from the inner shells of the neon atom, making it impossible for electrons from the outer shell to jumpt to those positions.

Once again, my guess is related to electrons in the outer shell of the Bohr planetary model. Only those electrons (called valence electrons) change energy levels and create spectral lines.

BTW: Only electrons in the outer shell are responsible for forming compounds with other atoms. For example, Sodium (Na) has one extra valence electron in the outer shell, while Clorine has an outer (valence) shell missing one electron for completeness. Hence NaCl (table salt) is formed by one sodium and two chlorine atoms.