Conductivity of materials -- What factors influence it?

[AybPhysics]

Hi Dear,
First of all I thank the administrators and the whole team that runs this forum for having accepted me to be part of this great family and also for the quality of this forum.

So, I have a question regarding conductivity which is an inherent property of material, Currently I take a course online, And professor mentioned that the conductivity depends on the number of valence electrons (the outer shell), But: Iron and Copper have the same number of valence electrons (= 2) and yet the conductivity of copper is higher.

My question then are the other factors that determines the intrinsic conductivity of a material ?
Thank you so much in advance for the answer and your time

 

[anorlunda]

That is a question that has a very complicated answer here in this Wikipedia article.
https://en.wikipedia.org/wiki/Free_electron_model

I confess that I don't understand much of it myself.

 

[AybPhysics]

Thank you so much #ANORLUNDA for your response, That link is useful and it helps me to understand how we can model the free electron and the justification. But I still don't knowing What other factors (other than free electrons) determine the conductivity of materials.

 

[anorlunda]

The first figure in that Wikipedia article says "In three dimensions, the density of states of a gas of fermions is proportional to the square root of the kinetic energy of the particles." Multiple energy states, kinetic energy distributions. Those are the key factors.

 

[AybPhysics]

Many thanks Anorlunda