Question

Specefically why metals are good conductor of heat

Answer 1

In metals, the outer electrons of the atoms belong to a 'cloud' of delocalised electrons. They are no longer firmly held by a specific atom, but instead they can move freely through the lattice of positive metal ions. ... Metals are good conductors of heat.

Answer 2

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.