GCSE Pearson Edexcel Separate Science Chemistry: Ionic and Covalent Structures

Simple covalent molecules

Molecules that contain only a few atoms held together by covalent bonds

Giant covalent structures

Contain many atoms held together by covalent bonds and arranged as a regular lattice

Intermolecular forces

The forces between molecules

Intramolecular forces

The forces inside a molecule, holding the atoms together

Polymer

A structure made of very large molecules, arranged in repeating patterns eg. plastics

Monomer

A molecule that can be bonded to other identical molecules to form a polymer

Natural polymers

Polymers that occur in nature eg. DNA, proteins and cellulose

Addition polymers

Polymers that are formed from simple linking of monomers

Displayed formula

A chemical formula showing all the bonds in the molecules as individual lines

Polymerisation

The reaction of monomer molecules to form long polymer chains

Alkene

A compound containing only carbon and hydrogen that contains a carbon-carbon double bond

Graphene

A form of carbon consisting of a single layer of atoms

Fullerenes

A form of carbon with fused rings making a partially closed mesh

Nanotubes

Tube-shaped molecules made up of carbon atoms

Conductor

A material that allows the flow of electrical charge through it

Insulator

A material that does not allow the flow of electrical charge through it

Catalyst

A substance that speeds up a chemical reaction but is not used up by it

Biodegradable

Description of a substance that can be decomposed by bacteria or other living organisms

Delocalised

Description of an electron that is not fixed to a particular atom but is free to move about

Anisotropic

Description of a material that has different values when measured in different directions e.g graphite