why does metal conduct electricity so well
of Metals The
structures of pure metals are simple to describe since the atoms
that form these metals can be thought of as identical perfect spheres. More specifically the metallic structure consists of 'aligned positive
ions' (cations) in a sea of delocalized electrons. This
means that the electrons are free to move throughout the structure,
and gives rise to properties such as conductivity. What
are different types of bonds? Covalent
covalent bond is a bond that is formed when two atoms share electrons. Examples of compounds with covalent bonds are, sugar and carbon
bonding is the complete transfer of valence electron(s) between
a metal and non-metal. This results in two oppositely charged ions
which attract each other. In ionic bonds, the metal loses electrons
to become a positively charged cation, whereas the nonmetal accepts
those electrons to become a negatively charged anion.
An example of an Ionic bond would be
Metallic bonds Metallic bonding is the result the electrostatic attractive force that occurs between conduction electrons (in the form of an electron cloud of delocalized electrons) and positively charged metal ions. It may be described as the sharing of free electrons among a lattice of positively charged ions (cations). Metallic bonding accounts for many physical properties of metals, such as strength, ductility, thermal and electrical resistivity and conductivity, opacity, and luster. Delocalized Moving electrons in Metals -- It is the free movement of electrons in metals that give them their conductivity. Metals contain free moving delocalized electrons. When electric voltage is applied, an electric field within the metal triggers the movement of the electrons, making them shift from one end to another end of the conductor. Electrons will move toward the positive side. Metal is a good conduction of heat.
Conduction occurs when a substance is heated, particles will gain more energy, and vibrate more. These molecules then bump into nearby particles and transfer some of their energy to them. This then continues and passes the energy from the hot end down to the colder end of the substance. Why do metals conduct heat so well? The electrons in metal are delocalised electrons and are free moving electrons so when they gain energy (heat) they vibrate more quickly and can move around, this means that they can pass on the energy more quickly. Which metals conduct the best? Silver has a larger atomic radius (160 pm) than gold (135 pm), despite the fact that gold has more electrons that silver! For a reason for this see the comment below. Silver is a better conductor than gold, but gold is more desirable because it doesn't corrode. (Copper is the most common because it is the most cost effective) First, let me explain why metals generally conduct heat better than other solids do.
In metals, some of the electrons (often one per atom) are not stuck to individual atoms but flow freely among the atoms. Of course, that's why metals are such good conductors of electricity. Now if one end of a bar is hot, and the other is cold, the electrons on the hot end have a little more thermal energy- random jiggling- than the ones on the cold end. So as the electrons wander around, they carry energy from the hot end to the cold end, which is another way of saying they conduct heat. Of course, how fast they conduct heat depends a lot on things like how many free electrons are around, on how fast they move, and especially on how far they usually go before they bump into something and change direction. Those are the same factors that determine how well the metal conducts electricity. So there's a rule that works very well, saying that the thermal conductivity of a metal (at some temperature) is proportional to the electrical conductivity.
That's convenient because it's much easier to measure electrical conductivity than thermal conductivity. So now I'll get a little closer to answering your question. The biggest factor giving different conductivities for ordinary metals is the difference in how far the electrons go before they hit something. It turns out, for amazing reasons connected with the wave nature of electrons, that they can flow right through a perfect crystal without bouncing, the same way light travels through a clear crystal. Lots of metals (stainless steel, brass, etc) are alloys of several elements, and the electrons bounce off all the irregularities in the arrangement of the different atoms. So those aren't good conductors. Even in a pure metal, the electrons still bounce some, because the thermal jiggling of the atoms keeps them from ever forming a perfectly exact crystal arrangement. Mike W. (published on 10/22/2007)
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