7. Answer briefly II

  

ii. AllotropyIsomerismTetravalencyCatenation: since carbon has a valency of \(4\), it can bond with four other carbon atoms or atoms of elements like oxygen, hydrogen, nitrogen, sulphur, chlorine etc.

 

Allotropy is a quality by which an atommetalmixtureelement can exist in more than one physically different and chemically similar form.

 

Carbon's two allotropy form is coal and graphitefullerene and charcoal charcoal and fullerenediamond and graphite.