This topic summary covers Knowledge Organiser: Ionic Bonding 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 16 of 16 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Knowledge Organiser: Ionic Bonding
Key Terms
- Ionic bond: electrostatic attraction between oppositely charged ions
- Cation (+): metal loses electrons
- Anion (-): non-metal gains electrons
- Electron transfer: electrons move from metal to non-metal
- Electrostatic attraction: force between opposite charges
Must-Know Facts
- Ionic bonding occurs between metals and non-metals
- Metals LOSE electrons → positive ions (cations)
- Non-metals GAIN electrons → negative ions (anions)
- Both ions achieve noble gas electron configuration
- Group 1 → +1, Group 2 → +2, Group 6 → -2, Group 7 → -1
- Dot-cross: outer shell only, brackets, charge outside
Key Equations
- Na → Na⁺ + e⁻ (metal loses electron)
- Cl + e⁻ → Cl⁻ (non-metal gains electron)
- Mg → Mg²⁺ + 2e⁻ (Group 2 loses 2 electrons)
- O + 2e⁻ → O²⁻ (Group 6 gains 2 electrons)
Common Mistakes
- Saying ionic bonding involves sharing electrons: Ionic = electron TRANSFER; covalent = electron SHARING — never confuse these
- Drawing ions without brackets and charges: Dot-cross diagrams for ionic compounds need square brackets with the charge written outside
- Wrong ion charges: Learn Group 1 = +1, Group 2 = +2, Group 6 = −2, Group 7 = −1
- Including inner shell electrons in dot-cross: Only draw the outer shell electrons in ionic bonding diagrams
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]
Quick recall flashcards
What is an anion?
A negative ion (formed when non-metals gain electrons)
What is a cation?
A positive ion (formed when metals lose electrons)