1.coz,the metals consist of atoms surrounded by electrons,the electros has electroconductivity.
2.It seems that the sodium has a better oxidability.Please check the sodium atom's nature and the periodic table of chemical element(atom or electro structure),seems it is very very easy to react with other elements,especially oxygen.
3.Plastics and ceramics have a great themal insulation ability,I don't know much about the plastics,but,i know more about the ceramics coz i am doing ceramics business.The ceramics has a melting poting between 1200- 1500 centigrades.Haha,it is almost barely melted at the normal high temperature; Ever there is a saying from a unknown artist,the ceramic is the most longevous thing created by human race.So,absolutely,it is the best material for the handle of some utensils.
I ever love physics and chemistry in my senior school time,but in the end,i lost myself!