How bonding and structure are related to the properties of substances key terms

ionic compound

A substance formed from the electrostatic attraction between oppositely charged ions.

strong attractions

Forces that act in all directions between oppositely charged ions in an ionic compound.

ionic compound

A substance formed from the electrostatic attraction between oppositely charged ions, typically resulting in a regular giant ionic lattice structure.

high melting point

The temperature at which an ionic compound transitions from solid to liquid, usually due to strong attractions between ions.

solid ionic compound

A solid ionic compound consists of a regular arrangement of ions held together by strong electrostatic forces, preventing the movement of charged particles.

conduct electricity

To conduct electricity means to allow the flow of electric current, which requires the presence of mobile charged particles.

molten ionic compound

An ionic compound that has been heated to a liquid state, allowing ions to move freely.

conduct electricity

The ability of a substance to allow the flow of electric current, typically due to the movement of charged particles.

ionic compound

A substance formed from the electrostatic attraction between oppositely charged ions, typically resulting in a regular giant ionic lattice structure.

conduct electricity

The ability of a substance to allow the flow of electric current, which in ionic compounds occurs when they are dissolved in water due to the mobility of ions.

ionic compound

In Properties of ionic compounds, ionic compound means a compound formed from the electrostatic attraction between oppositely charged ions. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to link electrical conductivity in ionic compounds to ions that are free to move. Use ionic compound only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

free-moving ions

Ions that are not fixed in place and can move freely, allowing for electrical conductivity.

small molecular substances

In Properties of small molecules, small molecular substances means substances that are usually gases or liquids at room temperature. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to describe small molecular substances as usually gases or liquids at room temperature. Use small molecular substances only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

room temperature

The typical temperature range (around 20-25°C) at which small molecular substances exist as gases or liquids.

melting point

In Properties of small molecules, melting point means the temperature at which a solid turns into a liquid. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to explain why small molecular substances often have low melting points and low boiling points. Use melting point only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

boiling point

In Properties of small molecules, boiling point means the chemistry idea used to explain why small molecular substances often have low melting points and low boiling points. Use this term specifically in How bonding and structure are related to the properties of substances when explaining this objective, so it is not confused with a broader bonding, structure, or materials term.

intermolecular forces

Forces that occur between molecules, which are overcome during the melting or boiling of small molecular substances.

small molecular substances

Substances that are usually gases or liquids at room temperature and consist of small molecules.

covalent bond

In Properties of small molecules, covalent bond means a strong bond formed when two atoms share electron pairs. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to explain that covalent bonds inside molecules are not broken during melting or boiling. Use covalent bond only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

melting or boiling

Processes where a substance changes state from solid to liquid or liquid to gas, respectively, without breaking covalent bonds.

melting point

In Properties of small molecules, melting point means the temperature at which a solid becomes a liquid. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to explain why larger molecules tend to have higher melting points and boiling points than smaller molecules. Use melting point only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

boiling point

In Properties of small molecules, boiling point means the chemistry idea used to explain why larger molecules tend to have higher melting points and boiling points than smaller molecules. Use this term specifically in How bonding and structure are related to the properties of substances when explaining this objective, so it is not confused with a broader bonding, structure, or materials term.

small molecular substances

Substances that are typically gases or liquids at room temperature and consist of small molecules.

conduct electricity

The ability of a substance to allow the flow of electric current, which small molecular substances usually do not possess.

intermolecular force

In Properties of small molecules, intermolecular force means the forces that exist between molecules, which are weaker than covalent bonds. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to use weak intermolecular forces compared with covalent bonds to explain bulk properties of molecular substances. Use intermolecular force only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

covalent bond

In Properties of small molecules, covalent bond means a strong bond formed when two atoms share one or more pairs of electrons. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to use weak intermolecular forces compared with covalent bonds to explain bulk properties of molecular substances. Use covalent bond only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

polymer

In Polymers, polymer means a very large molecule made from atoms linked by covalent bonds. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to describe polymers as very large molecules made from atoms linked by covalent bonds. Use polymer only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

covalent bond

In Polymers, covalent bond means the chemistry idea used to describe polymers as very large molecules made from atoms linked by covalent bonds. Use this term specifically in How bonding and structure are related to the properties of substances when explaining this objective, so it is not confused with a broader bonding, structure, or materials term.

polymer

In Polymers, polymer means a very large molecule made from atoms linked by covalent bonds. This matters in How bonding and structure are related to the properties of substances because it supports the learning objective to recognise polymers from diagrams showing bonding and structure. Use polymer only in this subtopic-relevant sense so the definition stays concise, curriculum-specific, and useful for AQA GCSE Biology revision. Students should use this term accurately when they explain the biology, identify symptoms, or justify an answer in GCSE Biology questions.

bonding structure

the arrangement of atoms and the type of bonds that determine the properties of a polymer.