$(1)$ Half-life of $^{14}C$ is $...........$
$(2)$ $..........$ isotope of carbon is used in radiocarbon dating.
$(3)$ Main component of ceramic,cement and glass is $........$

The name of the structure of silicates in which three oxygen atoms of $[SiO_4]^{4-}$ are shared is :-

Consider the following reactions:
$Me_3SiCl \xrightarrow{H_2O} A$
$Me_2SiCl_2 \xrightarrow{H_2O} B$
$MeSiCl_3 \xrightarrow{H_2O} C$
$A$,$B$,and $C$ are known as . . . . . . , . . . . . . ,and . . . . . . respectively in silicones formation.

Among the following,the correct statements are:
$I$. Germanium exists only in traces.
$II$. $PbF_4$ molecule is tetrahedral in shape.
$III$. $GeX_2$ is more stable than $GeX_4$.

Which of the following is not a monomer for a high molecular mass silicone polymer?

The stability of dihalides of $Si, Ge, Sn$ and $Pb$ follows the sequence.