Name the type of the structure of silicate in which one oxygen atom of $[SiO_4]^{4-}$ is shared?

The correct statements with respect to halides of group $14$ elements are:
$I$. Both $CCl_4$ and $SiCl_4$ undergo hydrolysis
$II$. $GeX_4$ is more stable than $GeX_2$
$III$. $PbX_4$ is less stable than $PbX_2$
$IV$. Stability of dihalides decreases down the group.

On strongly heating $Pb(NO_3)_2$ crystals,the gas formed is

Identify the correct statements from the following.
$(i)$ Quartz is a piezoelectric material.
$(ii)$ All group $14$ tetrachlorides except $CCl_4$ are easily hydrolyzed in water.
$(iii)$ The $C-C$ bond distance within the layer of graphite is $154 \ pm$.
$(iv)$ $SiO_2$ is soluble in aqueous $HCl$ solution.

Which of the following compounds of elements in group $14$ would you expect to be most ionic in character?

Which non-metals have high melting and boiling points? State them.