Topic 2 - Bonding. Structure, And Properties Of Matter

Question 1

What’s an ion

Answer 1

A charged particle

Question 2

What are positive ions called

Answer 2

Cations

Question 3

What are negative ions called

Answer 3

Anions

Question 4

What’s ionic bonding

Answer 4

• a metal and a non metal reacting together, the metal forms a positive ion and the non metal forms a negative ion
• the oppositely charged ions are strongly attracted to one another by electrostatic forces

Question 5

What’s the limitations of dot and cross diagrams

Answer 5

They don’t show the structure of the compound, the size of the ions, or how they are arranged

Question 6

What structure do ionic compounds have

Answer 6

Giant ionic lattice - closely packed regular lattice arrangement with strong electrostatic forces of attraction between the oppositely charged ions

Question 7

What are the properties of ionic compounds

Answer 7

• high melting and boiling points due to the many strong bonds between the ions
• conduct electricity when dissolved or molten

Question 8

What’s covalent bonding

Answer 8

Non metals sharing electrons - the positive nuclei are attracted to the negative electrons by electrostatic forces

Question 9

What are simple molecular substances made up of

Answer 9

Molecules containing a few atoms joined together by covenant bonds e.g water

Question 10

What are the properties of simple molecular substances

Answer 10

• low melting and boiling points as the forces of attraction between the molecules are weak
• most gases or liquid at room temperature
• don’t conduct electricity

Question 11

What’s a polymer

Answer 11

Lots of small units joined together to form a long molecule - joined by strong covalent bonds

Question 12

What’s a giant covelant structure

Answer 12

All the atoms are bonded to each other by strong covalent bonds e.g diamond

Question 13

What are the properties of giant covalent structures

Answer 13

• High melting and boiling points
• don’t conduct electricity (mostly) as it don’t contain charged particles

Question 14

Describe the structure of diamond

Answer 14

Each carbon atom forms 4 covalent bonds in a very rigid giant covalent structure

Question 15

What are the properties of diamnond

Answer 15

• very hard
• very high melting point
• doesn’t conduct electricity

Question 16

What’s the structure of graphite

Answer 16

Each carbon atom only forms 3 covalent bonds creating sheets of carbon atoms arranged in hexagons - no covalent bonds between the layers so they are free to move over each other

Question 17

What are the properties of graphite

Answer 17

• soft and slippery (ideal lubricating material)
• high melting point
• can conduct electricity - each carbon atom has one electron that’s delocalised

Question 18

What’s graphene

Answer 18

One layer of graphite

Question 19

What are the properties of graphene

Answer 19

• very strong and also very light (added to composite materials to improve their strength without adding much weight)

Question 20

What are fullerenes

Answer 20

Molecules of carbon shaped like closed tubes or hollow balls - mainly made up of carbon atoms arranged in hexagons but can also contain pentagons or heptagons

Question 21

What are fullerenes used for

Answer 21

• they could be used to deliver drugs to the body as they can ‘cage’ other molecules
• Good industrial catalysts - high surface area
• can form nanotubes - tiny carbon cylinders

Question 22

What are the allotropes of carbon

Answer 22

• diamond
• graphite
• graphene
• fullerenes

Question 23

What are the properties of nanotubes

Answer 23

• can conduct electricity and heat
• high tensile strength (stretchable)
• strengthen materials without adding weight

Question 24

What’s metallic bonding

Answer 24

• electrons in the outer shell of the electron are delocalised
• this creates strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons

Question 25

What’s an alloy

Answer 25

A mixture of two or more metals or a metal and another element- distorting the layers making them harder than pure metals as the layers can’t slide over each over

Question 26

How big are nanoparticles

Answer 26

They have a diameter between 1nm and 100nm

Question 27

What are nanoparticles used for

Answer 27

1) catalysts- large surface area to volume ratio
2) nanomedicine - delivering drugs ets - tiny particles absorbed more easily
3) tiny electrical circuts for computer chips
4) sliver nanoparticles - antibacterial propertie- surgical masks, wound dressings, deodorant etc
5) cosmetics - improving moisturisers etc
6) suncream- better coverage

Question 28

What are the downsides of the use on nanoparticles

Answer 28

• the way the affect the body isn’t fully understood- may be damaging
• May damage the environment