bonding structure and properties of matter

Question 1

what is a giant covalent structure

Answer 1

1) in a giant covalent structure all the atoms are bonded to each other by strong covalent bonds
2) they have very high melting and boiling points and lots of energy is needed to break the covalent bonds between the atoms
3) they do’t contain charged particles so they don’t conduct electricity - not even when molten
4) the main examples are diamond and graphite which are both made from carbon atoms

Question 2

what is the structure of diamond

Answer 2

1) diamond has a giant covalent structure made up of carbon atoms that form four covalent bonds. this makes diamond very hard
2) these strong covalent bonds take a lot of energy to break and give diamond a very high melting point
3) it doesn’t conduct electricity because it has no free electrons or ions

Question 3

what is the structure of graphite

Answer 3

1) in graphite each carbon atom only forms three covalent bonds creating sheets of carbon atoms arranged in hexagons
2) there aren’t any covalent bonds between the layers - they’re only held together weakly so they’re free to move over each other. this makes graphite soft and slippery so its ideal lubricating material
3) graphite has a high melting point - the covalent bonds in the layers need lots of energy to break
4) only three out of four of carbon’s outer shell electrons are used in bonds,so each carbon atom has one electron that’s delocalised and can move so graphite conducts electricity and thermal energy

Question 4

what is the structure of graphene

Answer 4

1) graphene is a sheet of carbon atoms joined together in hexagons
2) this sheet is just one atom thick making it a 2D substance
3) the network of covalent bonds makes it very strong. it’s also incredibly light so it can be added to composite materials to improve their strength without adding much weight
4) like graphite it contains delocalised electrons so it can conduct electricity through the whole structure. this means it has the potential to be used in electronics

Question 5

what is the structure of a fullerene

Answer 5

1) fullerenes are molecules of carbon shaped like closed tubes or hollow balls
2) they’re usually made up of carbon atoms arranged in hexagons but can also contain pentagons
3) fullerenes can be used to cage other molecules to the fullerene structure around another atom or molecule which is also then trapped inside. this could be used to deliver a drug in the body
4) fullerenes have a large surface area so they could help make great industrial cataylists. individual cayalist molecules could be attached to the fullerenes - fullerenes also make great lubricants