AQA Chemistry C2 Unit 1 & 2 - Structure, Bonding and Properties Key Words

Charged particle formed when atoms lose or gain electrons in order to produce a full outer shell.
Positive ion
Formed when metal atoms lose electrons from their outer shell.
Negative ion
Formed when non-metal atoms gain electrons to their outer shell.
Ionic bond
Electrostatic attraction between ions of opposite charge.
Ionic compound
Compound made up of positive and negative ions, key example: sodium chloride.
Covalent bond
Shared pair of electrons found between non-metal atoms.
Simple molecule
Molecule made up of a small number of atoms held by covalent bonds. Examples include water and ammonia. These are gasses and liquids because they are small molecules with only weak interactions between them.
Intermolecular forces (a.k.a. interactions)
Weak force found between molecules, causes them to have a low m.m. and b.p.
Regular arrangement of particles.
Giant covalent structure made up of a large number of atoms.
Each carbon forms 4 covalent bonds to other carbon atoms resulting in a very hard substance.
Each carbon bonds to three others in a layered structure. Layers only have weak interactions between them making the material soft and slippery. Conducts electricity because of spare electron being delocalized.
Giant structure of positive ions surrounded by a 'sea of electrons'.
Delocalised electrons
Electrons that are free to move. Found in graphite and metals and cause them to conduct electricity.
Based on particles a billionth of a meter in size.
Long chain molecule made from many small molecules (monomers) joined together.
Thermosoftening polymers
Can be melted and reshaped as have only weak interactions between chains.
Thermosetting polymers
Cannot be remolded as have strong cross links between chains.
Mixture of metals which is harder that a pure metal because the different sizes of atoms. These disrupt the layers in the structure making it harder for them to slide past each other.
Shape Memory Alloy
Return to original shape when deformed.
Buckminster Fullerine
A football shaped cage of carbons which is used to deliver drugs through membranes into cells.
Electron configuration
Illustrates the arrangement of electrons in their various shells. For example a Florine atom has a configuration [2,7] whereas a Florine ion has the configuration [2,8]⁻¹
Electron shell
Shows how electrons are arranged around the nucleus. The first electron shell contains a maximum of 2 electrons. 2nd=8, 3rd=8, 4th=18
Electrical conductivity
When a substance allows an electrical current to pass through it. This means that charges must be able to move and occurs in metals, graphite and molten ionic compounds.