Answer:Free-moving Electrons
Step-by-step explanation:
In metals which are good conductor of heat and electricity metals are free to move.This facilitate the conduction of heat and electricity through them.In both case delocalised electrons is responsible for conduction as they are not firmly attach to particular atom and are free to move.
Heat conduction is due to vibration of ions in the lattice, at heated end ions vibration is much more as compared to cold end and this vibration passed on to heat the metal.