Why are metals good conductors?

+58 votes
asked Apr 24, 2015 in Science by kerena (800 points)
Why are metals good conductors of heat and electricity? I came across this question in my homework and I’m kind of stuck. Why only metals? What is different of them that materials like plastic don’t do the same? Is it the way they are molecularly composed?

1 Answer

+20 votes
answered May 3, 2015 by moyann (900 points)

Metals are such good conductors of heat and electricity all because the way they are molecularly bonded.

We shall have a brief look of what makes a metal, a metal in first place. Properties of metal are malleable and ductile, yet most are still strong and durable. The strength of metal suggests that the atoms are difficult to separate, however, their “softness” in the form of ductility and malleability indicates that the structure allows for easy movement. With a good electrical conductivity, electrons can move freely in any direction in metal. In addition, thermal conductivity involves these electrons motions as well. So we have a property that shows a strong atom bond, yet electrons are free to move in any direction in the material.

Let’s picture how these electrons are in a metal. Imagine a sea or a cloud of these delocalized electrons, travelling freely among through the lattice of positive metal ions, the lattice structure that makes the metal stronger than most substance. If we introduce electricity, these randomly moving electrons could carry an electrical charge; if the metal is formed into a wire, these electrons could then be directed to move from the “negative” to the “positive”. For head conductivity, these electrons would carry kinetic energy instead, travelling through the structure, slowly covering the whole lattice with heat. So the main difference between metals and none insulators is the fact that insulators do not have free moving electrons within their structure to do all the work.

commented May 6, 2015 by Shelbey (800 points)
Wow, now I know why are metals good conductors of heat and electricity. Thanks for the help.
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