Need an explanation of shells in layman's terms

[Woopy]

We just did atomic physics in class, and my teacher assumed everyone had already taken chemistry so she really skimmed through the material, and I have yet to take chemistry so I am beyond lost with this chapter. I read the chapter and it is so technically written that I don't comprehend it well. I was wondering if anyone out there could answer a few of my questions via skype and answer some stuff in layman's terms so that I can actually start doing the homework. Thank you

please PM if you can do this

 

[Anaxandridas]

By "shells," your teacher means quantum states that are indexed by quantum numbers. In layman's terms, the shell is described by a principal quantum number n which corresponds to the mean radial distance of the electron from the nucleus.

Within a shell there are subshells that describe other characteristics of the electrons quantum state including: angular momentum (indexed by l), how the angular momentum changes in the presence of an externally applied magnetic field (indexed by m), and the spin orientation of the electron (indexed by s).

So when you hear the term "shell"... just think that an atom has a finite number of quantum states which an electron can occupy... and the "shells" roughly describe the mean radial expanse of a particular set of states.