Which of the following inert gases participates in chemical reactions?

$SbF_5$ reacts with $XeF_4$ to form an adduct. The shapes of cation and anion in the adduct are respectively:

The density of nitrogen prepared from air is slightly higher than that of nitrogen prepared from chemical compounds. This is due to the presence of which of the following in nitrogen obtained from air?

State the uses of noble gases.

The reason for the lowest boiling point of $He$ is...

The elements with atomic numbers $10$,$18$,$36$,$54$,and $86$ are all