Allotropes

Question 1

Allotrope

Answer 1

A different form of an element in the same physical state with different bonding within the structure. Carbon has many allotropes.

Question 2

Diamond

Answer 2

4 Carbons bonded together in a tetrahedral structure sp3 hybridized with 109.5. Part of the Giant Covalent molecules, network solid, macro-molecules.

Question 3

Does diamond conduct electricity?

Answer 3

No, it has fixed e-

Question 4

Characteristics of diamond

Answer 4

Hardest substance/brittle, excellent thermal conductor, transparent crystals, used to cut glass and in jewelry.

Question 5

Graphite

Answer 5

Each C bonded to 3 other Cs, sp2 hybridized, 120 bond angles, hexagonal structure, many layers. Part of giant covalent molecules.

Question 6

Characteristic of graphite

Answer 6

High melting/boiling points, conductor of electricity due to delocalized e-, not conductor of heat, soft and slippery due to layers slipping over each other. Dark grey, shiny solid. Used in pencils and lubricants.

Question 7

Graphene

Answer 7

Same as graphite but only one layer

Question 8

Characteristics of graphene

Answer 8

Conducts electricity (delocalized e-), thermal conductor, almost fully transparent, flexible with tensile strength, photo-voltaic cells and electronics. Thinnest material to exist but strength is 100 times steel and 40 times diamond.

Question 9

Fullerene/Bucky Ball C60

Answer 9

Each C bonded in a sphere of 60 carbon carbon atoms. 12 pentagons and 20 hexagons. Sp2 hybridization. Not Giant Covalent molecule has a fixed formula (C60)

Question 10

Characteristics of Fullerene

Answer 10

Semi-conductor - some delocalized e- in the hexagon. Low thermal conductivity. Low Mpt/Bpt. Flexible, yellow crystalline solid. Biomedical uses.