How many electrons do the elements of the most stable group have in their outer energy levels?

If they are the most stable, it must mean they have a full outer shell. the first shell can only hold 2 so if it only has 2 electrons then it is pretty stable. all other shells after that can hold 8 so if it has 10,18,26,34,42 and etc electrons, it will be stable as well. 

hope this helps!

The most stable group is the Noble Gases, which is group 8. They need 8 valence electrons to be stable. The electrons are determined by their group number.

It has to be b i hope this