These are all good questions! Based on your description I assume you haven't had an introduction to solid state physics yet? Let's take your image of an electron that "jumps"
from atom to atom. In my understanding I wouln't describe it that way, to me it's a wavefunction of the electron that is almost independent from the valence electrons and you
can use the free electron gas approximation. Why is this band independent? See the following picture for an intuitive understanding:
![Potential leading to different bands][1]

I think most of your questions will be easier to answer if you make yourself familiar with basic concepts and approximations people use to describe electrons in a solid first. Sure, a lot of things can be understood if we consider electrons to be little spheres that scatter from bigger spheres (ions), but you said you want to understand on the **atomic level** -> it's good to see the electron as a wave and see how this wave behaves in a lattice with certain boundary conditions.

First, I would read about a crystal. Atoms are arranged in a periodic lattice (assume a nice crystal for a first simple picture) and you can make assumptions based on this periodicity. You can define a unit cell and the Brillouin zone. You will see that the energy levels will sometimes split up in different bands and based on the filling of these bands you end up wih a metal, insulator etc. Electrons are fermions, can two electrons be in the same state? This defines the Fermi velocity.

This filling of the available energy levels describes the Fermi surface, a very useful tool
to describe other more advanced concepts. Then you will see what happens if you change the arrangements of the atoms or why in what spatial directions electrons can move due to the bonding of different atomic orbitals.

This could be a good start ; ) ->
http://britneyspears.ac/lasers.htm

There are other introductions out there, most of them describe the basics really well.


  [1]: https://i.sstatic.net/k2a3A.gif