Answer:
Option B,D
Explanation:
Diamond has a three-dimensional network- structure, a hard substance where graphite is soft due to layered structure. In graphite, only three valence electrons are involved in bonding and one electron remains free giving electrical conductivity. ln diamond, all the four valence electrons are covalently bonded hence, insulator.
Diamond ls a better thermal conductor than graphite. Electrical conductivity is due to the availability of free electrons, thermal conduction is due to transfer of thermal vibrational energy from one atom to another atom. Compact and precisely aligned crystals like diamond thus facilitate better movement of heat
In graphite C-C bond acquire some double-bond character, hence, higher bond order than in diamond.
