Conductivity is the ability of a substance to allow charge or electricity to pass through it. Metals have a lot of free electrons and are considered as good conductors while non-metals do not conduct electricity
1) In the given examples:
Al is a metal, Na is an alkali metal while P is a non-metal
The decreasing order of conductivity would be:
Al > Na > P
2)
Both Al and Ga are metals while B is metalloid.
Among Al and Ga, Al is a solid at room temperature and a better conductor of electricity. hence the decreasing order would be:
Al > Ga > B
