Answer:
It is more difficult to remove electrons from a noble gas than it is to remove electrons from elements in other groups.
Explanation:
Let me restate here that in the noble gases, the outermost shell is filled. Owing to this full shell, noble gases has the outermost eight electrons required for any specie to attain stability.
It is very difficult to remove an electron from a closed shell. This is why the first ionization energy of noble gases is usually far higher than that of elements from other groups.