Answer :
The answer is (3)Ne. Usually, the elements belongs to group 18 all have completely filled valence electron shell. Among the four elements carbon, vanadium, neon and antimony, only neon belongs to group 18.
In the ground state, the atom that has a completely filled valence electron shell is NEON, Ne.
In the periodic table of elements, the elements that have completely filled valence electron shell are the noble gases and neon is one of them. The noble gases has eight electrons each in their outermost shells, this makes them to be stable and thus, they are unreactive in nature. The other elements in the periodic table usually undergo chemical reactions in order to have eight electrons in their outermost shells just like the noble gases.
