1) It has low reactivity. 2) They are inert to chemical they are also called inert gases. 3) They don't form compounds with other elements except xenon 4) the reactivity order is as follows: Ne< he
1 3 1
The two conditions for a gas to behave as an ideal gas are :
1. Their valency should be zero i.e. the number of electrons in the outermost shell should be filled totally.
2. It should have low reactivity with other elements in the nature.
1 2 1