Carbon Allotropes

Question 1

Name all carbon allotropes

Answer 1

Diamond, graphite, graphene fullerene C60

Question 1

outline the diamond structure and its properties

Answer 1

structure: each carbon atom is surrounded by four other carbon atoms in a giant covalent structure (netowrk covalent)

bonds: strong covalent bonds
melting/boiling point: very high due to covalent bonds
conductivity: poor as it has no delocalised electrons

IMF: none literaly, as the structure is continous.

Question 2

outline the graphite structure and its properties

Answer 2

structure: each carbon atom is covalently bonded to three other carbon atoms in a layered structure. A graphite crystal is composed of layers on top of one another

IMF: layers are held together by relatively weak London dispersion forces

conductivity: Each carbon atom has an electron which becomes delocalised across the plane. can conduct.

strenght: soft, malleable

melting/boiling point: still high due to covalent bonds but not as high as diamond

Question 3

Properties and structure of fullerene C60

Answer 3

Simple covalent structure

made up of carbon atoms bonded together in 20 hexagons (six-carbon rings) and 12 pentagons (five-carbon rings) like in a football

Like graphite, each carbon atom is covalently bonded to 3 other carbon atoms.
cotains 60 Carbon atoms

conductivity: C60 does have delocalised electrons but the electrons cannot jump between individual fullerenes, therefore, it is a poorer electrical conductor than graphite.

Question 4

propeties of graphene

Answer 4

a single layer of graphite that has been isolated, so covalent bonds between C atoms that are bonded to 3 other C.

high electrical and thermal conductivity due to delocalised e-

Very reactive due to unoccupied bonds in the edges of the structure

soft, very malleable

Question 5

give examples og giant covalent structures

Answer 5

diamond and silicon dioxide and graphite

Question 6

what are giant covalent structures

Answer 6

consist of a vast network of atoms bonded together by covalent bonds.

Question 7

outline prperties of silicon dixodie

Answer 7

SiO2 is a very hard substance, a poor conductor of electricity at low temperature and has a high melting and boiling point.