Do electrons literally travel in order to change the charge of a substance? Do valence electrons literally break free of their bonds and jump from substance(1) to substance(2) in case of charging by conduction? If so, how? Do these electrons remain suspended amongst other atoms in substance(2) P.S. I'm in middle school so I would prefer a simplified explanation and/or links to certain concepts I should read about to help my understanding.
 A: Yes you are right, electrons do get transferred from 1 substance to other, but they form ions not isotopes.
For example when we run comb on a dry hair, comb gets excess of elctrons, or becomes negatively charged, which then by induction creates a positive charge on small paper pieces.
So side of paper facing comb gets positively charged (devoid of electrons) which are then attracted to the comb. After touching comb, electrons are transferred and charges gets balanced, until there is no net charge on either comb or paper.
Isotopes on other hand are formed when an atom of an element gets extra neutrons in their nucleus which changes physical properties of the atom of the element. This has nothing to do with ions.
A: Kshitij's answer describes correctly the charging of insulators by rubbing.  The OP asks about charging by conduction. In this case the electrons transfered are the free,  conduction electrons.  These don't have to break free, they are already so, they just transfer from one conductor to another.  They move through the lattice made of positive ions, in both conductors.  And this structure of positive ions and free electrons exists even in equilibrium,  when there is no excess charge. A charged conductor simply have an excess (or deficit ) of free electrons; the core ions are not involved.
