Giant covalent structures
3 marks · EasyState the electrical conductivity for each of the following carbon structures: diamond, graphite, and C60 fullerene.
Explain why diamond does not conduct electricity.
Explain why graphite conducts electricity.
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(a) Diamond: does not conduct | Graphite: conducts well | C60 fullerene: does not conduct · must show Diamond: does not conduct, Graphite: conducts, C60: does not conduct
(b) All electrons in diamond are held in covalent bonds and none are free to move. · must show No free electrons
(c) Graphite has delocalised electrons that are free to move throughout the layers. · must show Delocalised electrons, Move throughout layers
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States correct conductivities for all three: diamond (no), graphite (yes), C60 (no).
B1 (b) · 1 mark · Explains diamond does not conduct due to all electrons being held in covalent bonds.
B1 (c) · 1 mark · Explains graphite conducts because it has delocalised electrons that move through the layers.
Worked solution
a) Diamond does not conduct; graphite conducts; C60 fullerene does not conduct. b) In diamond, all electrons are used in covalent bonds, so none are free to move. c) In graphite, some electrons are delocalised and can move through the layers, allowing it to conduct electricity.