Ionic compounds
Introduced| English | Meaning |
|---|---|
| giant lattice/ˈdʒaɪənt ˈlætɪs/ | giant lattice |
| molten/ˈməʊltn/ | In the liquid state after being melted by heating. |
| dissolved/dɪˈsɒlvd/ | dissolved |
Giant grids of ions
- A single grain of salt contains trillions of ions, locked in a perfect repeating pattern.
- Ionic compounds form giant lattices 巨型晶格 — and this structure explains all their properties.
Ionic compounds form a:
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A giant 3D lattice of ions forms.
The regular 3D arrangement of ions in an ionic compound is called a ______.
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A giant ionic lattice.
The giant ionic lattice
- Ionic compounds are giant lattices of oppositely charged ions.
- Strong forces attract the ions in all directions, in a regular 3D pattern.
Ions pack into a giant lattice: a regular pattern of alternating positive and negative ions
Ionic bonding (electron transfer)
Step through it: the metal hands its outer electron(s) to the non-metal, both reach full shells, and the resulting + and − ions attract.
Ionic compounds have high melting points because:
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Strong ionic attractions need lots of energy to break.
High melting points
- The strong attractions between ions take a lot of energy to break.
- So ionic compounds have high melting and boiling points and are solid at room temperature.
An ionic compound conducts electricity when:
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Conduction needs free-moving ions.
A solid ionic compound conducts electricity well.
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Its ions are locked in place, so it does not conduct.
Conducting electricity
- Ionic compounds conduct only when molten 熔融 or dissolved 溶解的 — when the ions are free to move.
- As a solid, the ions are locked in place, so it does not conduct.
Solid ionic compounds don't conduct. The ions are fixed in the lattice. Only when melted or dissolved can the charged ions move and carry a current.
You've got it
- ionic compounds are giant lattices of oppositely charged ions
- strong attractions → high melting/boiling points
- they conduct only when molten or dissolved (free ions), not when solid