The arrangement of carbon atoms in diamond is tetrahedral and therefore the hybridization of carbon atoms is sp3. Graphite is the more common form and has a density of. Macromolecules Igcse Grade 9 And 10 Chemistry Quizizz It is not classified as an element. . Diamond and graphite are two crystalline forms of carbon. In these allotropes of carbon the atoms consisting of carbon atoms in that of the Diamond and. Diamond and graphite are made out of carbon atoms. Diamond is the hardest natural substance and hence Y is diamond. So we can conclude that X to carbonY to diamondZ to graphite. Y is the hardest natural substance whereas Z is a good conductor of electricity. For instance allotropic forms are the different physical forms of a element that have chemical properties in common. Because diamond is the hardest natural substance Y is a diamond. Since X exists in two forms Y and Z Y and Z are known as the all...