Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Formulae for ionic compounds
18 practice questions
Practice questions
1–3 of 3 · Hard
Question 1
2 marks · Hard
Answer and see the solution →Iron(III) oxide is an ionic compound formed from Fe3+ and O2– ions. State the correct formula for iron(III) oxide and explain why this is the correct formula.
Question 2
5 marks · Hard
Answer and see the solution →Potassium ions (K+) and phosphate ions (PO4^3–) combine to form an ionic compound.
(a)[2 marks]State the symbol and charge of the potassium ion and the phosphate ion.
(b)[3 marks]Explain, with working, how to deduce the simplest formula for the ionic compound formed from these ions.
Question 3
2 marks · Hard
Answer and see the solution →State the formula for the ionic compound formed between ammonium ions and nitrate ions. Explain your answer.