Re: why do the atom's energy level names start with 'K' and then move up to 'q'

Darryl,

The model of electrons in shells was created by Bohr after seeing inconsistencies in Rutherford's model (which should have electrons losing energy and spiralling into the nucleus), and then linking work on the emission spectrum of hydrogen (Balmer equation) to Planck's work on quantisation of energy. This was the dawn of quantum mechanics, of course.

Electrons are only allowed to be in one shell or another, and nowhere in between (like books on shelves). Transitions between shells produce the lines in the emission spectrum when an excited atom returns to the ground state.

I haven't been able to confirm this answer, but I remember my own Chemistry teacher telling me that he started with the letter K to "future proof" his model against the possibility of further shells being found to be closer to the nucleus.

Of course it is much more common to use the principle quantum number (n=1 for the K shell) nowadays. As to why it goes up to Q, well this represents n=7, which is the outermost occupied shell in the ground state of the largest elements (the bottom row of the periodic table begins with the 7s sub-shell)

Hope this is what you were looking for. A search for Bohr Model on any search engine will turn up loads of useful links where you can read about this fascinating period in the history of science.

nigel