C3 Flashcards
What structure do the ionic compounds have?
A giant ionic lattice
Name some properties of ionic compounds
High melting/boiling points
Why do ionic compounds have high melting/boiling points?
Due to the many bonds between the ions
When do ionic compounds conduct electricity?
When molten or dissolved. This is because their ions can become mobile and can carry charge through the liquid
What is meant by intermolecular forces?
Forces of attraction between the atoms
Why does a diamond have a high melting point?
It has a giant covalent structure with strong covalent bonds holding the atoms closely into regular giant lattices
What properties do simple molecules have?
Stong covalent bonds and weak intermolecular forces
How strong is the force of attraction between simple molecular substances?
Very weak although they are held together by strong convalent bonds
Do simple molecular compounds conduct electricity?
No because they are not charged
What happens in a giant covalent structure?
In a giant covalent structure, all the atoms are bonded to each other by strong covalent bonds.
What are delocalised electrons?
Electrons that are free to move around
Name the two forms of element carbon
Diamond and graphite
What do chemists call different forms of the same element in the same state?
Allotropes
List the properties of a giant covalent structure
Very high melting and boiling points, hard, insoluble in water, electical insulator
What is the structure of a diamond?
It is a giant covalent structure with each carbon atom forming four covalent bonds in a very rigid giant covalent structure.
What is the structure of graphite?
It is a giant covalent structure with each carbon atom forming three covalent bonds to create layers of hexagons and each carbon atom has one delocalised electron therefore it conducts electricity
What are the graphite layers?
In graphite each carbon atom only forms 3 covalent bonds creating sheets of carbon atoms. The sheets arent connected with any covalent bonds between the layers - they are only held together weakly - so they are free to move over each other
What is graphene?
Graphene is one layer of graphite ( sheet )
What are fullerenes?
Fullerenes are molecules of carbon shaped like closed tubes or hollow balls
How can fullerenes be used to transport drugs into the body?
Fullerenes can be used to ‘cage’ other molecules so the fullerene structure forms around another atom or molecule that is then trapped inside
What does metallic bonding involve?
It involves delocalised electrons
What happens in a metals outer shell?
The electrons in the outer shell of the metal atoms are delocalised. There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons. These forces of attraction hold the atoms together in a regular structure and are known as metallic bonding
What is an alloy?
A mixture of metals
List all the properties of metals
Most metals are solid at room temp
Metals are good conductors of electricity and heat
Most metals are malleable ( the layers of atoms can slide over each other )
Alloys are harder than pure metals
What is the word for something that can be drawn out into a wire (stretched)
Ductile
What is nanoscience?
It is the study of small particles that are between 1 and 100 nanometres in size
Surface area to volume ratio =
Surface area / volume
What can nanoparticles be used in?
- They could help make new catalysts
- can be used to make tiny electric circuits because they can conduct electricity
- they can be used in cosmetics
1 nanometre = m
1 * 10 -9
