The physical properties of ionic substances
2 marks · HardDescribe the arrangement of sodium and chloride ions in the giant ionic lattice of sodium chloride.
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Each sodium ion is surrounded by six chloride ions and each chloride ion is surrounded by six sodium ions. This pattern repeats throughout the crystal.
Also accept: Each Na^+ is surrounded by 6 Cl^- ions, each Cl^- by 6 Na^+ ions, in a regular repeating pattern.
Common mistakes: Saying sodium chloride forms molecules.; Not mentioning the number of neighbouring ions.
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Marking points
B1 · 1 mark · States Na^+ surrounded by six Cl^- and Cl^- by six Na^+ ions.
B2 · 1 mark · References repeating/regular pattern throughout the structure (giant lattice).
Worked solution
In sodium chloride, each sodium ion (Na^+) is surrounded by six chloride ions (Cl^-), and each chloride ion is surrounded by six sodium ions. This arrangement repeats throughout the giant lattice.