Question

why were noble gas and their compounds discover late

Answer 1

The noble gasses are inert or unreactive due to the fact that they all follow the rule of octet and have complete s^2p^6 orbital arrangements in the highest energy level.

Because most elements were discovered through their reactivity with other elements, typically with oxygen, it was difficult for scientists to work with a substance that seemed to have little or no chemical properties based upon the lack of reactivity.

I hope this was helpful.

Answer 2

Because most elements were discovered through their reactivity with other elements, typically with oxygen, it was difficult for scientists to work with a substance that seemed to have little or no chemical properties based upon the lack of reactivity.