Electrons are positioned in concentric shells around the nucleus. The first shell maxes out at just 2 electrons. The next holds 8, then it goes up to 18, etc. In the noble gases, how are these shells unique?

Question

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1 point
They need just 1 more electron to be full
All the shells are completely filled
The electrons are in random orbits

Answer 1

In noble gases, all the shells are completely filled. This is what makes them stable and less reactive than other elements, as they have a full outer electron shell. Thus, the correct answer is:

All the shells are completely filled