Silicon is an important constituent of

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.

Choose the correct statement from the following with reference to the inert pair effect.

Why does carbon differ from the rest of the members of its group? Explain.

Diamond and emerald are forms of which of the following respectively?

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