Question

In graphite, electrons are:
A.localised on each C-atom
B.localised on every third C-atom
C.spread out between the structure
D.present in anti-bonding orbital

Answer 1

Graphite is one of the allotropes of carbon, the other being diamond. The carbons in graphite are arranged in a hexagonal structure. Each carbon is bonded with three other carbon atoms which leave one free electron. This is the reason why graphite is a good conductor of electricity.

Complete step by step answer:
Graphite is a form of pure carbon. It is the most stable form of carbon in normal temperature. Each carbon atom in graphite is ${\text{s}}{{\text{p}}^{\text{2}}}$ hybridised. Each carbon is covalently bonded with three other carbon atoms in the same plane. This one layer is called graphene. The layers are bonded with each other weakly by Vander Waal forces. This is the reason why graphite is slippery and can be used in pencil leads. As carbon is a tetravalent element, one electron remains free in each carbon atom. As all the carbons are ${\text{s}}{{\text{p}}^{\text{2}}}$ hybridised, the single occupied un-hybridised p-orbital of carbon atoms overlap side wise to give a pi-electron cloud which is delocalised. Thus, the electrons are spread all over the graphite structure. These electrons can travel freely throughout the structure and thus, graphite is a good conductor of electricity.

$\therefore$ The correct option is option C, i.e. the electrons are spread out between the structure.

Note:
Graphite is the only non-metal which conducts electricity. It is used as electrodes, batteries and even in solar panels. The other allotrope of carbon, i.e. diamond is an insulator and the hardest material on earth. The carbons are all ${\text{s}}{{\text{p}}^{\text{3}}}$ hybridised with each carbon atom covalently bonded to four other carbon atoms.