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Magnesium oxide is an ionic compound. lonic compounds are generally soluble in water. State two other properties of ionic compounds. Voce eect
See it on the paper →Solid sodium chloride has a lattice structure. Put a tick ( ✓ ) next to the statement that describes this lattice structure. giant structure of atoms with strong bonds between the atoms irregular arrangement of random positive and negative ions regular arrangement of alternating positive and negative ions simple molecu...
See it on the paper →Draw the electronic structures of the sodium ion and chloride ion in the ionic compound sodium chloride. Show the charges on the ions.
See it on the paper →Describe the structure of sodium chloride.
See it on the paper →Explain why molten sodium chloride conducts electricity, but solid sodium chloride does not conduct electricity.
See it on the paper →Ionic compounds, such as lithium chloride, have a lattice structure. Describe the lattice structure of ionic compounds. You may include a labelled diagram if you wish.
See it on the paper →Fig. 8.3 shows an incomplete diagram of part of the structure of a sodium chloride crystal. Complete the diagram by showing the arrangement of sodium ions, Na + , and chloride ions, Cl – . Cl – (ions are not drawn to scale) Fig. 8.3
Very occasionally candidates attempted to draw sodium and chloride ions as being covalently bonded. Most candidates were able to draw ions with the correct number of electrons in their outer shell. Very occasionally the charges were muddled or absent.
— Examiner report, February/March 2024, 0654/42 Q2(b)(i) (Cambridge)
Several candidates misinterpreted this question and described the bonding of sodium chloride, referring to the loss and gain of electrons to form an ionic bond. Stronger candidates described the structure with reference to a regular or lattice structure. Very few candidates described the structure in terms of alternating positive and negative ions.
— Examiner report, February/March 2024, 0654/42 Q2(b)(ii) (Cambridge)
A common misconception was to explain the conduction of electricity in terms of the movement of delocalised electrons rather than mobile ions.
— Examiner report, February/March 2024, 0654/42 Q2(b)(iii) (Cambridge)
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