This exam focus covers Worked Model Answer within Ionic Bonding for GCSE Chemistry. Revise Ionic Bonding in Bonding & Structure for GCSE Chemistry with 35 exam-style questions and 20 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 15 of 16 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
📝 Worked Model Answer
Question: "Explain how ionic bonding occurs in sodium chloride (NaCl)." (4 marks)
Sodium has one electron in its outer shell, which it transfers completely to a chlorine atom. [1] This means sodium now has more protons than electrons, so it becomes a positively charged sodium ion, Na⁺, with the stable electron configuration 2,8. [1] Chlorine gains this electron, giving it more electrons than protons, so it becomes a negatively charged chloride ion, Cl⁻, with the stable electron configuration 2,8,8. [1] Because the Na⁺ and Cl⁻ ions carry opposite charges, there is a strong electrostatic force of attraction between them — this is the ionic bond. [1]
Examiner note: The four mark points are: (1) electron transfer from sodium to chlorine, (2) sodium becomes Na⁺, (3) chlorine becomes Cl⁻, (4) electrostatic attraction between opposite ions forms the ionic bond. Students who only say "electrons are shared" score zero — this is the most common fundamental error. Mentioning "stable electron configuration" or "full outer shell" is rewarded but not required for every mark point.
Practice questions for Ionic Bonding
Which combination of elements forms an ionic compound?
Describe the structure of an ionic compound and explain why ionic compounds have high melting points. [3 marks]