BONDING AND STRUCTURE

Question 1

what bonds are in a giant covalent structure?

Answer 1

all the atoms are bonded by strong covalent bonds

Question 2

what are the properties of a giant covalent structure?

Answer 2

🌡very high melting and boiling points - lots of energy required to break the covalent bonds
🌡They don’t have any ions, so they don’t conduct electricity. even when they are molten
🌡 they are insoluble in water

Question 3

give three examples of giant covalent structures?

Answer 3

💎diamond
💎graphite
💎silicon dioxide

Question 4

properties of a diamond?

Answer 4

💎it has 4 covalent bonds
💎 exceptionally hard
💎 has a boiling point of 4827°
💎 arranged in a perfect giant lattice

Question 5

what are the properties and structure of graphite?

Answer 5

✏️only 3 bonds forming hexagons
✏️ in layers connected by weak intermolecular forces. this means the layers can slide making it a soft and slippery material
✏️there is one spare electron which can move freely throughout the layers
✏️ delocalised electrons mean they can conduct electricity and thermal energy

Question 6

what are fullerenes?

Answer 6

fullerenes are a structure of carbon atoms that join together to create a hollow shape.
the structure is based on hexagonal rings however some are made up of pentagonal or heptagonal carbon atoms

Question 7

what was the first fullerene to be discovered?

Answer 7

buckminsterfullerene which was made up of 60 carbon atoms in a spherical form

Question 8

how are fullerenes used?

Answer 8

👩‍🔬to deliver drugs into the body
👩‍🔬as lubricants
👩‍🔬as catalysts because they have a large surface area to volume ration

Question 9

what are cylindrical fullerenes called?

Answer 9

carbon nanotubes

Question 10

what are the properties of cylindrical fullerenes?

Answer 10

🎾the have high tensile strength ( they are capable of being drawn out or stretched)
🎾high electrical and thermal conductivity ( because bonding gives them a delocalised electron)

Question 11

what is graphene?

Answer 11

graphene is a single layer of graphite. it is a layer of hexagonal rings. around 1 atom thick

Question 12

what are the properties of graphene?

Answer 12

👉good conductor of thermal energy and electricity (even better than graphite
👉has a very low density
👉most reactive form of carbon

Question 13

properties of metallic structures?

Answer 13

➕ metal ions are arranged in regular layers
➕ the outer electron from each metal atom can move freely throughout the structure to form a SEA OF DELOCALISED ELECTRONS
➕strong electrostatic attraction between the electrons and the metal ions hold the structure together
➕able to slide over eachother due to tightly packed layers, therefore, are extremely mailable

Question 14

what is an alloy?

Answer 14

an alloy is a mixture of metals. for example, steel is made up of iron and carbon. carbon atoms are much bigger than iron atoms making ht layers uneven and harder for them to slide over one another.
this makes alloys harder than metals

Question 15

uses of metallic structures?

Answer 15

🙃 good conductors of thermal energy and heat

🙂 this is because they have high melting points

Question 16

how do the metal ions hold together?

Answer 16

the delocalised electrons are connected by electrostatic forces of attraction

Question 17

why are metallic structures malleable?

Answer 17

because the electrons can move while holding the electrostatic forces, the lattice can distort.
when struck, the metals can slip past one another without braking up the metallic structure

Question 18

why do metallic structures have high melting points?

Answer 18

the electrostatic forces of attraction extend in all directions within the lattice and requires a lot of energy to break up.

Question 19

what is the diameter of a nanoparticle?

Answer 19

1nm to 100nm

Question 20

how do nanoparticles behave?

Answer 20

nanoparticles have a high surface area to volume ratio, meaning that they are more reactive than normal particles

Question 21

what are the uses of nanoparticles

Answer 21

👉🏻cosmetics - they are used in deodorants and face creams as they absorb deeper into the skin
👉🏻medicine - carbon nanocages are used to deliver drugs. in wound dressings, silver nanoparticles are used to protect the skin against bacteria
👉surface area to volume ration makes them effective catalysts