CIE iGCSE Co-Ordinated Science C2.4 Ions and ionic bonds Exam Style Questions Paper 2
▶️ Answer/Explanation
The ammonium ion has a charge of \(+1\) and the phosphate ion has a charge of \(-3\); to achieve electrical neutrality, 3 ammonium ions are needed for every 1 phosphate ion.
Therefore the formula is \((\text{NH}_4)_3\text{PO}_4\), giving a total charge of \(3(+1) + (-3) = 0\).
✅ Answer: (A)
Therefore the formula is \((\text{NH}_4)_3\text{PO}_4\), giving a total charge of \(3(+1) + (-3) = 0\).
✅ Answer: (A)
▶️ Answer/Explanation
Sodium chloride is formed by ionic bonding, in which sodium atoms transfer electrons to chlorine atoms, forming \(\text{Na}^+\) and \(\text{Cl}^-\) ions, not neutral atoms.
These oppositely charged ions are held together by strong electrostatic forces in a giant lattice, arranged in a highly regular, repeating pattern rather than randomly.
So the structure consists of a regular, alternating arrangement of sodium ions and chloride ions.
✅ Answer: (D)
These oppositely charged ions are held together by strong electrostatic forces in a giant lattice, arranged in a highly regular, repeating pattern rather than randomly.
So the structure consists of a regular, alternating arrangement of sodium ions and chloride ions.
✅ Answer: (D)
▶️ Answer/Explanation
Non-metal atoms typically form ions by gaining electrons (to complete their outer shell), not by losing them.
Statement B has this backwards, so it is incorrect.
Statements A, C and D are all true descriptions of ion formation and behaviour.
✅ Answer: (B)
Statement B has this backwards, so it is incorrect.
Statements A, C and D are all true descriptions of ion formation and behaviour.
✅ Answer: (B)
▶️ Answer/Explanation
Since \(\text{Na}_3\text{PO}_4\) balances three \(\text{Na}^+\) ions, the phosphate ion must carry a charge of \(\text{PO}_4^{3-}\).
Aluminium ions carry a charge of \(\text{Al}^{3+}\), deduced from \(\text{Al}_2(\text{SO}_4)_3\) balancing two \(\text{Al}^{3+}\) against three \(\text{SO}_4^{2-}\).
Since \(\text{Al}^{3+}\) and \(\text{PO}_4^{3-}\) have equal and opposite charges, they combine in a 1:1 ratio, giving the formula \(\text{AlPO}_4\).
✅ Answer: (A)
Aluminium ions carry a charge of \(\text{Al}^{3+}\), deduced from \(\text{Al}_2(\text{SO}_4)_3\) balancing two \(\text{Al}^{3+}\) against three \(\text{SO}_4^{2-}\).
Since \(\text{Al}^{3+}\) and \(\text{PO}_4^{3-}\) have equal and opposite charges, they combine in a 1:1 ratio, giving the formula \(\text{AlPO}_4\).
✅ Answer: (A)
Question
The bonding in potassium iodide is ionic.
Which row describes the potassium iodide lattice structure?
▶️Answer/Explanation
Ans: C