${\mathrm{He}}_2$ does not exist. Why?
 

Draw the structure of the product $\mathrm{A}$ formed in the following reactions:

$\mathrm{Xe}\left(\mathrm{g}\right) + {\mathrm{F}}_2\left(\mathrm{g}\right) \stackrel{ 873\mathrm{K}, 7\mathrm{bar} }{\to } \mathrm{A}\left(\mathrm{s}\right)$
 

Draw the structure of the product $\mathrm{A}$ formed in the following reactions:

${\mathrm{XeF}}_6 + {\mathrm{H}}_2\mathrm{O} \stackrel{ }{\to } \mathrm{A} + \mathrm{HF}$

Write any two uses of helium.
 

 Write any two uses of the following:

Neon

Complete the following chemical equation:

${\mathrm{XeF}}_2 + {\mathrm{PF}}_5 \stackrel{ }{\to }$

Complete the following chemical equations:

${\mathrm{PCl}}_{5 }+ {\mathrm{H}}_2\mathrm{O} \left(\mathrm{excess}\right) \stackrel{ }{\to }$