Hint: Heat conductivity or thermal conduction is the transport of energy across a temperature gradient because of random molecular motions. Heat flow follows the process of conduction which depends upon the presence of free electrons.
Complete answer: Metals are considered to be very good conductors of heat because of the following reasons: First, the metal ions are closely packed in the metal lattice, and then the transfer of heat from one end to another is more efficient as compared to the non-metals.
Next, the availability of free electrons makes the transfer of heat easier, and thus, it results in making the metals a good conductor of heat. Here are examples of three very good conductors of heat. Aluminium, Silver, Iron.
There are various factors on which the thermal conductivity or we can say the reason to make the metals are good conductors of heat depends. Like, material structure, the density of the material, the moisture content, and the temperature and pressure of the operating condition.
Additional Information: Conduction is defined to be a process in which heat energy is transmitted through the collisions between the neighbouring atoms and the molecules. In this case, the vibrating molecules collide with the neighbouring molecules and make them vibrate much faster than usual. As these molecules collide with each other, the thermal energy is transferred through the process of conduction to the rest of the material.
Note: We should not get confused between the two processes of heat transfer; conduction and convection. In convection, the heat transfer occurs due to the flow of substance and it generally happens in case of fluids in which the density changes due to the application of heat. but in case of solid substances, the heat transfer takes place internally due to the vibrations between the atoms and molecules.