Which of the following noble gases forms interstitial compounds with metals?

The synthetically produced radioactive noble gas by the collision of ${}_{98}^{249}Cf$ with ${}_{20}^{48}Ca$ is

In $XeF_2, XeF_4, XeF_6$,the number of lone pairs on $Xe$ is respectively:

Which of the following elements among $He, Ar, Kr,$ and $Xe$ forms compounds in the least amount?

Assertion $(A)$: $Xe$ atoms in $XeF_2$ are $d^2 s p^3$ hybridised.
Reason $(R)$: $XeF_2$ molecule does not follow the octet rule.
Which of the following is correct?

In noble gases,the addition of successive electronic shells leads to a decrease in their ........ .