Individual atoms do not have the physical properties of the substances that contain them. For example, a copper atom cannot conduct electricity, even though a piece of copper can do this. Bulk properties are properties due to many atoms, ions or molecules acting together.
|Type of substance||Example(s)||Bonds broken||Relative bond strength|
|Simple molecular||Oxygen, water||Intermolecular forces||Weak|
|Ionic substance||Sodium chloride||Ionic bonds||Strong|
|Giant covalent||Silicon oxide, diamond||Covalent bonds||Strong|
|Metal||Magnesium, sodium||Metallic bonds||Strong|
Simple molecular substances:
Malleable substances can be bent or hammered into shape without shattering. Metals are malleable. When a force is applied, layers of metal ions can slide over each other while still being attracted to the ‘sea’ of delocalised electrons.
A substance can conduct electricity if both:
|Type of substance||Conducts electricity?||Reason|
|Simple molecule||No||Simple molecules are not charged|
|Ionic compound||Only when molten or dissolved||Ions are charged particles, free to move about when the substance is molten or dissolved (not when it is solid)|
|Giant covalent||No||The individual atoms are not charged|
|Metal||Yes||Contains delocalised electrons, free to move about|