All noble gases crystallize in $ccp$ structure. Which one is an exception?

The density of nitrogen obtained by the liquefaction of air is higher than that of nitrogen obtained by chemical reactions from nitrogenous compounds. This is due to the presence of which gas in the atmospheric nitrogen?

Which one of the following does not exist?
$(i)$ $XeOF_{4}$
$(ii)$ $NeF_{2}$
$(iii)$ $XeF_{2}$
$(iv)$ $XeF_{6}$

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

Assertion $(A)$: The boiling points of noble gases increase from $He$ to $Xe$.
Reason $(R)$: The interatomic van der Waals' attractive forces increase from $He$ to $Xe$.
The correct answer is:

Which of the following is the correct series of noble gases in the periodic table?