Lanthenoid are good conductor of heat and electricity why?

Lanthanoids are good conductor of heat and electricity due to following reasons.

(1) They are typical metallic in nature/structure.

(2)They have delocalised free unpaired electrons for electrical conductivity.

(3) Unpaired electrons gain energy and vibrate around thair nucleus, and hence energy transfer take palace to another nearby electrons which leads to transfer of heat energy as well.