Bulk properties
Individual The smallest part of an element that can exist. do not have the physical The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point. of the substances that contain them. For example, a copper atom cannot To allow electricity, heat or other energy forms to pass through. electricity, even though a piece of copper can do this. Bulk properties are properties due to many atoms, Electrically charged particle, formed when an atom or molecule gains or loses electrons. or A collection of two or more atoms held together by chemical bonds. acting together.
Melting and boiling points
Chemical The chemical link that holds molecules together. are broken or overcome during The process that occurs when a solid turns into a liquid when it is heated. and boiling. The stronger these bonds are, the higher the The temperature at which a solid changes into a liquid as it is heated. and The temperature at which a substance rapidly changes from a liquid to a gas..
| 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 |
| Type of substance | Simple molecular |
|---|---|
| Example(s) | Oxygen, water |
| Bonds broken | Intermolecular forces |
| Relative bond strength | Weak |
| Type of substance | Ionic substance |
|---|---|
| Example(s) | Sodium chloride |
| Bonds broken | Ionic bonds |
| Relative bond strength | Strong |
| Type of substance | Giant covalent |
|---|---|
| Example(s) | Silicon oxide, diamond |
| Bonds broken | Covalent bonds |
| Relative bond strength | Strong |
| Type of substance | Metal |
|---|---|
| Example(s) | Magnesium, sodium |
| Bonds broken | Metallic bonds |
| Relative bond strength | Strong |
Simple Refers to a substance made up of molecules, so it contains small groups of atoms, of a set size, held together by covalent bonds. substances:
- have relatively low melting and boiling points
- are usually gases or liquids at room temperature, or solids that are easily melted
Ionic substances form when a metal reacts with a non-metal. They contain charged particles called ions., giant A covalent substance is a molecule containing one or more covalent bonds (shared pairs of electrons). substances and Shiny element that is a good conductor of electricity and heat, and which forms basic oxides.:
- have relatively high melting and boiling points
- are usually solids at room temperature
Malleable or brittle
Capable of being hammered or pressed into a new shape without being likely to break or return to the original shape. substances can be bent or hammered into shape without shattering. Metals are malleable. When a A push or a pull. The unit of force is the newton (N). is applied, layers of metal ions can slide over each other while still being attracted to the 鈥榮ea鈥 of Electrons that are not associated with a particular atom, eg in a metal, outer electrons can be free to move through the solid. Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons..
Ionic substances and giant covalent substances are usually If something is brittle it is easily broken.. They shatter when bent or hit because many strong Ionic bonding forms between two atoms when an electron is transferred from one atom to the other, forming a positive-negative ion pair. or A bond between atoms formed when atoms share electrons to achieve a full outer shell of electrons. break at once.
Conducting electricity
A substance can To allow electricity, heat or other energy forms to pass through. electricity if both:
- it contains Particles, usually ions or electrons, that carry electrical charges.
- these charged particles are free to move about
| 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 |
| Type of substance | Simple molecule |
|---|---|
| Conducts electricity? | No |
| Reason | Simple molecules are not charged |
| Type of substance | Ionic compound |
|---|---|
| Conducts electricity? | Only when molten or dissolved |
| Reason | Ions are charged particles, free to move about when the substance is molten or dissolved (not when it is solid) |
| Type of substance | Giant covalent |
|---|---|
| Conducts electricity? | No |
| Reason | The individual atoms are not charged |
| Type of substance | Metal |
|---|---|
| Conducts electricity? | Yes |
| Reason | Contains delocalised electrons, free to move about |
Note that A form of pure carbon in which all the atoms are bonded to three others in giant sheets which can slide over each other., A form of carbon consisting of a single layer of carbon atoms joined together in hexagonal rings. and Molecules of carbon with hollow shapes. Their structures are based on hexagonal rings of carbon atoms. are covalent substances that do conduct electricity. This is because, like metals, they contain delocalised electrons.