Assertion : Inert gases are monoatomic.
Reason : Inert gases have stable configuration.

Among the fluorides below,the one which does not exist is

The noble gases have closed-shell electronic configuration and are monoatomic gases under normal conditions. The low boiling points of the lighter noble gases are due to weak dispersion forces between the atoms and the absence of other interatomic interactions.
The direct reaction of xenon with fluorine leads to a series of compounds with oxidation numbers $+2, +4$ and $+6$. $XeF_4$ reacts violently with water to give $XeO_3$. The compounds of xenon exhibit rich stereochemistry and their geometries can be deduced considering the total number of electron pairs in the valence shell.
$1.$ Argon is used in arc welding because of its
$A.$ low reactivity with metal
$B.$ ability to lower the melting point of metal
$C.$ flammability
$D.$ high calorific value
$2.$ The structure of $XeO_3$ is
$A.$ linear
$B.$ planar
$C.$ pyramidal
$D.$ $T$-shaped
$3.$ $XeF_4$ and $XeF_6$ are expected to be
$A.$ oxidizing
$B.$ reducing
$C.$ unreactive
$D.$ strongly basic
Give the answer for questions $1, 2$ and $3$.

What is the general electronic configuration of noble gases other than helium?

Match List-$I$ with List-$II$ and select the correct answer using the codes given below the lists:

List-$I$	List-$II$
$(A) \ XeF_4$	$(1) \ \text{Distorted octahedral}$
$(B) \ XeF_6$	$(2) \ \text{Tetrahedral}$
$(C) \ XeO_3$	$(3) \ \text{Square planar}$
$(D) \ XeO_4$	$(4) \ \text{Pyramidal}$

Helium is used in balloons in place of hydrogen because it is