i believe you are talking about the noble gases.........they are unreactive because they already have a stable electron configuration and need no more......the reason most substances react is because they are unstable a and need more valence electrons.....
The neon family, or noble gases, has a full outer electron shell containing 8 electrons. This means that each noble gas in the neon family has 8 valence electrons, which makes them stable and unreactive.
Group VIII, the noble gases.
It is because zeon is a noble gas &unreactive
8 valence electrons are there in in neon's family .They are stable in nature.
group 8, the noble gasses.
In short, an element's valence shell is full and most stable when it contains eight electrons (this stability is the reason that the noble gases are so unreactive).
Neon - one of the stable and unreactive elements of group 8.
Unreactive
All the elements in the Inert Gases family (exc. Radon) are highly unreactive. The Inert Gases family occupies Group 18(0) of the Periodic Table. They each have 8 electrons in the outer shell. The Inert Gases Group contains;HeliumNeonArgonKryptonXenonRADON
Noble Gasses.
The element is 'argon' and belongs to noble gas family.
Inert means unreactive, and most of these gases never react.