The Noble gases are relatively unreactive.
The Nobel gases have a full stable octet, which means the outer shell of the atom has eight electrons.
Due to which:
- Noble gases have high Ionization energy because to remove an electron from full stable octet is difficult.
- Noble gases have low electron affinity, as full octet is present hence, no attraction for the incoming electron exists
The reactivity of the element is based on the ability to form ions by gaining or losing electrons to get the octet stability and as above said Noble gases already have a stable octet so they are the least reactive.