Question

Why are the noble gases the most stable elements
on the periodic table?

Answer 1

because their valance shell (outermost shell) is completed with the maximum number of electrons

Step-by-step explanation:

Answer 2

They have eight valence electrons, which fill their outer energy level

Step-by-step explanation:

Noble gases are the least reactive of all elements. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds.