C2.3 - Properties Of Materials Flashcards
What group is carbon in?
Group 4
How many electrons does carbon have in its outer shell
4 electrons
How many covalent bonds can carbon form?
4
How does carbon form chains and rings?
By joining with other carbon atoms
How does carbon produce different compounds?
Carbon atoms in chains and rings can form covalent bonds with other elements, producing different compounds
What is an allotrope
Forms of an element in the same state but with different atomic arrangements
What are some allotropes of carbon
Diamond
Graphite
Graphene
How many covalent bonds does diamond have
Each carbon atom is covalently bonded to 4 other carbon atoms
What are some properties of diamond?
High melting point
Hard
It is transparent
Does not conduct electricity
What are some uses of diamond?
Tips of dental drills
Can diamond conduct electricity
No
Why can’t diamond conduct electricity
All the outer electrons in its atoms are shared so It has no delocalised electrons
How many covalent bonds does each carbon atom form in graphite?
3
Can graphite conduct electricity
Yes
Why can graphite conduct electricity
It has one delocalised electron in the outer shell of each atom.
This electron is free to move throughout the structure so it can conduct electricity
What are some properties of graphite?
Giant covalent structure
Layered structure
Slippery
High melting point
What shape do the atoms in each layer of graphite form
Interlocking hexagons
What is graphene?
A carbon allotrope that resembles a single layer of graphite
What are some properties of graphene
Almost transparent
Strong
Conducts electricity
What can graphene be used to make
Flexible touch screens
What are fullerenes
A family of carbon allotropes in which the molecules are shaped like tubes or balls
What is a nanotube
A type of fullerene in which carbon atoms form a hollow tube
It resembles a sheet of graphene rolled into a tube
Properties and uses of nanotubes
Strong
Used to reinforce sports equipment
What is a buckyball
A type of fullerene
It is a hollow spherical molecule made from carbon atoms arranged in pentagons or hexagons
What are uses of buckyballs
Lubricants
Might be able to deliver medicine to cells
What does brittle mean
A substance that breaks when a force is applied
Why are metals malleable?
Metal ions are held in a lattice by forces that attract them to delocalised electrons
When an external force is applied the layers of metal ions can over each other
Because the delocalised electrons are free to move, no bonds are broken
Why are giant covalent structures brittle
If a large force is applied many covalent bonds break at once and the substance breaks
Why are some materials soft and flexible
Because they have weak intermolecular forces are their particles are not arranged in a lattice
What is a nanoparticle
It is a particle between 1nm and 100nm across and consists of only a few hundred atoms
What is the size of one nanometer in standard form
1 x 10^-9
What is a nanoparticulate
A material that is made from nanoparticles
What are examples of materials in bulk
Grains
Lumps
Sheets
What can nanoparticles be used for
New sunscreens
New cosmetics
New medicines
New paints
New catalysts to speed up industrial chemical reactions
Self cleaning clothes and windows
What are risks of nanoparticles
They are soo small that they can be :
breathed in
Absorbed by the skin
Pass into cells
They could take a long time to break down once they are released into the environment
Toxic substances could stick to their surfaces
