Hard but brittle
Physical nature of ionic compounds.
A salt crystal
A crystal of an ionic compound is pressed hard.
What will it do?
What this lesson covers
The idea
Ionic compounds are solids and somewhat hard because of the strong force of attraction between their positive and negative ions; they are generally brittle and break into pieces when pressure is applied.
A salt crystal
A crystal of an ionic compound is pressed hard.
What will it do?
- Break into pieces
- Bend like a wire
- Flow like a liquid
Press the crystal
Press Next step.
Hard and brittle
The strong attraction between positive and negative ions makes ionic compounds solid and somewhat hard. They are generally brittle: when pressure is applied they break into pieces.
Ionic compounds are solids and somewhat hard because of the strong force of attraction between their positive and negative ions; they are generally brittle and break into pieces when pressure is applied.
Notes
Ionic compounds are solids, somewhat hard (strong ion attraction) and generally brittle: they break into pieces under pressure.
Check yourself
Ionic compounds are ...
What makes ionic compounds somewhat hard?
When pressure is applied to an ionic compound, it generally ...
- solids that are somewhat hard — correct. Yes!
- gases. The book says ionic compounds are solids.
- soft liquids. The book says ionic compounds are solids and somewhat hard.
- Their lustre. Lustre is the shine of metals, not the reason for hardness.
- The strong attraction between positive and negative ions — correct. Yes!
- Their being made of molecules. Ionic compounds are made of ions, not molecules.
- bends without breaking. Ionic compounds are generally brittle, so they do not bend.
- is drawn into a wire. Drawing into wires is ductility, a property of metals.
- breaks into pieces — correct. Yes!