The last element of group-$14$ is found to be

An oxide of an element is a gas and dissolves in water to give an acidic solution. The element belongs to:

Which of the following elements exhibit metallic nature among $C$,$Si$,$Ge$,$Sn$,and $Pb$?

$A$ thin layer of aluminum deposited on glass acts as a good mirror because ...............

Which of the following statements are correct?
$1.$ Charcoal can be obtained by heating wood in the absence of air.
$2.$ Charcoal is an impure form of graphite.
$3.$ Diamond is thermodynamically the most stable allotrope of carbon.
$4.$ Coke is used as an oxidising agent during the extraction of iron from its ores.

What are allotropes? Sketch the structure of two allotropes of carbon namely diamond and graphite. What is the impact of structure on physical properties of these two allotropes?