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Conduction in Metals

Conduction is one of the basic property of the metal. But conduction in metals differ, this difference
in the conductivity can be explained using Band Theory
Let us consider the metal Copper (Cu) the electronic configuration of Cu and its energy level diagram
can be written as
When a di atomic Cu is formed the moecular obrital diagram can be written as
But in metallic Cu there are N number of atoms so molecular orbital diagram for Natoms can be given as
In the molecular orbital diagram of N-atoms the bonding molecular orbitals of valence
shell are collectively termed as Valance band. Similarly the anti bonding molecular
orbitals of valance shell are termed as Conduction band.
The difference in the energy between the valance band and conduction band is the
deciding factor of the property of metal conductor
During conduction the electrons jump from valance band to conduction band, lesser the energy
required for the transition, higher would be the probability of electron to jump thus the conductor
would be higher so metal would behave as very good conductor. But as the energy gap is relatively
higher the transition would require higher energy thus the transition would be not easier, thus the
resistance of metal would increase
In a solid, like copper, aluminum, and steel, these atoms are arranged on a crystal lattice (yes, metals
are actually crystalline!). On a microscopic level, heat is conducted via something called phonons
(essentially lattice/atomic vibrations) and free electrons. For metals, the ability of a material to
conduct heat is tied predominantly with how far electrons travel without being scattered. It is no
coincidence metals are both good electrical and thermal conductors. Metals have free electrons,
which can also carry heat. The electrons can scatter off of a variety of things like defects, impurities,
or lattice vibrations The last one is what really differs between two crystalline materials like copper
and aluminum, which have different bonding characters and atomic masses. Steel does worse for
similar reasons, and also because it has carbon impurities, which inhibit the transfer of heat.
For non-metals, heat is no longer transferred via electrons because there are no free electrons to
carry the heat. Instead, they are carried by phonons.