Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Principles of Chemistry
991 practice questions
Topics covered
- States of Matter102 practice questions
- Elements, Compounds and Mixtures69 practice questions
- Atomic Structure108 practice questions
- The Periodic Table103 practice questions
- Chemical Formulae, Equations and Calculations Part 119 practice questions
- Chemical Formulae, Equations and Calculations Part 2144 practice questions
- Ionic Bonding143 practice questions
- Covalent Bonding68 practice questions
- Metallic Bonding19 practice questions
- Electrolysis198 practice questions
Practice questions
91–100 of 161 · Hard
Question 91
2 marks · Hard
Answer and see the solution →A calcium atom (Ca) forms a Ca ion. Describe what happens to the atom when it forms this ion and explain why it forms an ion with a charge of 2+.
Question 92
5 marks · Hard
Answer and see the solution →Phosphorus is a Group 5 element with atomic number 15.
(a)[1 mark]Describe how a phosphorus atom forms a phosphide ion ().
(b)[1 mark]Write the electronic configuration of a phosphide ion.
(c)[2 marks]Explain why the phosphide ion is isoelectronic with a noble gas atom. Name the noble gas.
(d)[1 mark]State the total number of electrons in a phosphide ion.
Question 93
2 marks · Hard
Answer and see the solution →Explain why a bromide ion () has the same number of electrons as a krypton atom.
Question 94
2 marks · Hard
Answer and see the solution →Describe how electrons are transferred when a lithium atom and a fluorine atom react to form lithium fluoride. Your answer should explain how this transfer leads to the formation of ions.
Question 95
5 marks · Hard
Answer and see the solution →Calcium chloride is formed when calcium reacts with chlorine.
(a)[1 mark]State the electronic configuration of a calcium atom and a chlorine atom.
(b)[2 marks]Explain how calcium and chlorine atoms achieve full outer shells when forming calcium chloride.
(c)[2 marks]Draw a dot-and-cross diagram to show the ions formed in calcium chloride. Show only the outer shells.
Question 96
2 marks · Hard
Answer and see the solution →State the charge on each ion and the number of electrons in the outer shell of each ion in lithium fluoride.
Question 97
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 98
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 99
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.
Question 100
2 marks · Hard
Answer and see the solution →Lead(II) bromide (PbBr_2) is an example of a giant ionic compound. Explain why solid lead(II) bromide does not conduct electricity, but molten lead(II) bromide does.