How electrons in valency and flow as they are connected to the atom and the atom is stationary but the electron travels way more distance than the size of atom that causes conduction?
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3$\begingroup$ What do you mean with "atom that causes conduction" and what is "electrons in valency " $\endgroup$– trulaCommented Aug 11 at 17:30
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2$\begingroup$ These might help - Definition of metallic state, Fermi level and conductivity $\endgroup$– mmesser314Commented Aug 11 at 17:36
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2$\begingroup$ Can you write this question more clearly. "How electrons in valency and flow..." I don't understand what this means? $\endgroup$– Brendan DarrerCommented Aug 12 at 6:28
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1$\begingroup$ Roughly speaking valence electrons are shared between atoms, because as they are in the outermost shells, they are loosely coupled with current atom at hand and are free to change the owner as any neighboring atom force perturbation happens. $\endgroup$– Agnius VasiliauskasCommented Aug 13 at 10:35
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2 Answers
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They are not connected to any specific atom. The description of electrons belonging to one particular atom makes sense for isolated atoms, but it doesn't work like that in conducting solids. Even in something like the tight binding approximation, where you model the solid as electrons belonging to specific atoms with the attraction by other atoms as a perturbation, the result is that the relevant electrons end up in superpositions of belonging to many different orbitals of many different atoms. That is, in very delocalized states, that spread over the whole crystal.
A good intro is David Tong's lecture notes on solid state physics, he talks all about the tight binding model and the nearly free electron model and how they are connected.
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In metals the valence electrons are delocalised and do not belong to a particular atom. In insulators they are localised on a particular atom.
To be localised an electron will increase its momentum and hence its kinetic energy. This is what quantum mechanics teaches us. Delocalised electrons on the other hand feel the repulsion of other electrons more strongly.
If the kinetic energy cost is higher than the repulsion, delocalisation occurs. If repulsion dominates, localisation happens. This is the idea of the Hubbard model. Check it out!
