Ionic Bonding
Year 8 ⚛️ Particles & Structure Describe ionic bonding as electron transfer; write ionic formulae.
🔗 What is Ionic Bonding?
Ionic bonding involves the transfer of electrons from a metal to a non-metal, forming oppositely charged ions that attract each other.
Metals LOSE electrons → positive ions (cations). Non-metals GAIN electrons → negative ions (anions).
NaCl formation:
Na → Na⁺ + e⁻ (loses 1 electron)
Cl + e⁻ → Cl⁻ (gains 1 electron)
Na⁺ and Cl⁻ attract electrostatically → ionic bond.
Na → Na⁺ + e⁻ (loses 1 electron)
Cl + e⁻ → Cl⁻ (gains 1 electron)
Na⁺ and Cl⁻ attract electrostatically → ionic bond.
📐 Ionic Formulae
The formula of an ionic compound is determined by balancing the charges of the ions (overall charge must = 0).
| Compound | Ions | Ratio | Formula |
|---|---|---|---|
| Magnesium chloride | Mg²⁺, Cl⁻ | 1:2 | MgCl₂ |
| Aluminium oxide | Al³⁺, O²⁻ | 2:3 | Al₂O₃ |
| Sodium oxide | Na⁺, O²⁻ | 2:1 | Na₂O |
🏗️ Properties of Ionic Compounds
Properties Explained by Structure
$$\text{High melting points} \leftarrow \text{strong electrostatic forces in lattice}$$
$$\text{Conduct when molten or dissolved} \leftarrow \text{ions free to move}$$
$$\text{Do NOT conduct when solid} \leftarrow \text{ions fixed in lattice}$$
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Interactive Demonstration — Ionic Bonding
See how electrons transfer to form ions in ionic bonding.
🔗 Ionic Formula Builder
Work out the formula of an ionic compound from ion charges.