Simple molecular structures
2 marks · NormalExplain why substances with simple molecular structures do not conduct electricity, even when melted.
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Must show: molecules do not have free electrons or ions, no mobile charge carriers present
Also accept: Their particles are neutral; no charged particles free to move,
Common mistakes: thinking molecules split into ions on melting
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Marking points
B1 · 1 mark · State there are no free electrons or ions.
B2 · 1 mark · Explain that there are no mobile charge carriers to conduct electric current.
Worked solution
Substances with simple molecular structures do not conduct electricity because their molecules do not have free electrons or ions. There are no mobile charge carriers, so no electric current can flow.