Why metal is the best conductor of heat?
Metals are good conductors of heat. There are two reasons for this: the close packing of the metal ions in the lattice. the delocalised electrons can carry kinetic energy through the lattice.
For example, copper is used for electrical wiring because it is a good conductor of electricity. Metal particles are held together by strong metallic bonds, which is why they have high melting and boiling points. The free electrons in metals can move through the metal, allowing metals to conduct electricity.
- In a conductor, electric current can flow freely, in an insulator it cannot. Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them.
- While all metals can conduct electricity, certain metals are more commonly used due to being highly conductive. Another common misconception is the pure Gold is the best conductor of electricity. While Gold does have a relatively high conductive rating, it is actually less conductive than Copper.
- Metals conduct electricity. The delocalised electrons are free to move throughout the structure in 3-dimensions. They can cross grain boundaries. Even though the pattern may be disrupted at the boundary, as long as atoms are touching each other, the metallic bond is still present.
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.
- Thermal and electrical conductivity. Why are metals good conductors of heat and electricity? Electric current is the flow of electrons in a wire. They are no longer firmly held by a specific atom, but instead they can move freely through the lattice of positive metal ions.
- Metallic bonding forms a closely packed lattice structure of positive ions with delocalized electrons (these are the electrons of the outer shell of the metal atom). Because these electrons are delocalised, they can move freely within the metal structure when an electrical current is applied.
- In a conductor, electric current can flow freely, in an insulator it cannot. Metals such as copper typify conductors, while most non-metallic solids are said to be good insulators, having extremely high resistance to the flow of charge through them. Most atoms hold on to their electrons tightly and are insulators.
For metals, the thermal conductivity is mainly a function of the motion of free electrons. As the temperature increases, the molecular vibrations increase (in turn decreasing the mean free path of molecules). So, they obstruct the flow of free electrons, thus reducing the conductivity.
- For semiconductors and insulators, as the temperature increases, some of the electrons acquire energy and become free for conduction. As the conductivity of a solution is dependent on these factors then an increase in the solution's temperature will lead to an increase in its conductivity.
- An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the ions in the metal. As the temperature increases, the metal ions vibrate more. There are more collisions with the electrons and so the resistance increases.
- For metals, the thermal conductivity is mainly dependent on the motion of free electrons. As the temperature increases, the molecular vibrations increase thus increasing the mean free path of molecules. So, they obstruct the flow of free electrons, thus reducing the conductivity.
Updated: 4th October 2019