CBSE Class 10 Answered

Diamond

Graphite

Buckminster fullerene

In diamond the carbon atoms are covalently bonded to one another producing a three dimensional network solid.

Graphite is also made of carbon atoms. Graphite consists of carbon atoms covalently bonded together in a layers made up of hexagons, like chicken wire.

Buckminsterfullerene (Bucky ball) is an allotrope of carbon that is produced by firing high powered laser beams at graphite.

Each carbon atom is bonded to four other atoms throughout the crystal lattice.

Each carbon atom has three bonds and one free electron.

Each molecule consists of a large number of carbon atoms covalently bonded to one another forming a sphere (similar to a soccer ball).

Diamond has no free electrons because they are all involved in bonding and is therefore a poor conductor of electricity.

The extra electrons are delocalised and can be moved along the layers by applying an external voltage. This is why graphite can conduct an electric current.

They are extremely stable in nature.
They are inert.
They have aromaticity which means they are stable and inert carbon bonds.
Soluble in many solvents and are the only carbon allotrope that are soluble. 
Their hollow structure allows them to hold other atoms inside them.

Diamond is the hardest substance known and is used to cut glass and in industrial drill bits.

Graphite unlike diamond is extremely soft.

Diamond is widely sought after because of its rarity and unique cystalline structure and is used in jewellery.

The parallel layers of graphite are weak intermolecular bonds, which allow the layers to easily slip over each other. This is what happens when writing or drawing with a graphite pencil on paper.