The noble gases are a group of chemical elements with very similar properties. a unique feature of this group of elements is that they are known to be very inert, or unreactive, with other chemicals. what would be the best explanation for the low reactivity of these elements?

The correct answer is - the outermost shell of these elements are because their outermost shell of electrons is full (valency).

Explanation:

The noble gases are the chemical elements that are inert, or unreactive with any other chemicals. Elements tries to complete to the outer shell by gaining, sharing, or loosing the electron.

This is the reason the that cause the inertness of the noble gases and does not  takes part in the reaction,  The noble gases have complete outer shell so their is no need to share, gain or loose to stable the element.

Thus, the correct answer is -  the outermost shell of these elements are because their outermost shell of electrons is full (valency).

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex