Topic 2 -Bonding, structure, and the properties of matter

Question 1

Describe the structure of an ionic compound.

Answer 1

1. They are structured in a giant ionic lattice
2. There are very strong electrostatic forces of attraction between oppositely charged ions, in all directions.

Question 2

Why do ionic compounds have high melting/boiling points?

Answer 2

Due to the strong bonds between ions, which require a lot of energy to overcome.

Question 3

Why can’t molecular compounds conduct electricity?

Answer 3

They aren’t charged, so there ar no delocalised electrons or ions to carry charge through the substance.

Question 4

What is a polymer?

Answer 4

A polymer is a substance made up of many smaller monomers linked to form a long molecule with repeating sections.

Question 5

Why do simple molecular structures have low melting/boiling points?

Answer 5

1. The covalent bonds are very strong, but the intermolecular forces are very weak, so they require very little energy to overcome.

Question 6

Why do giant covalent structures have high melting/boiling points?

Answer 6

1. Lots of energy is needed to overcome the very strong covalent bonds.

Question 7

What are examples of giant covalent structures?

Answer 7

1.diamond
2.graphite
3.silicon dioxide

Question 8

What is the structure of a diamond?

Answer 8

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

Question 9

What is the structure of Graphite?

Answer 9

Each carbon atom forms 3 covalent bonds to create layers of hexagons. Each carbon atom also has one delocalised electron.

Question 10

What is silicon dioxide?

Answer 10

Sand

Question 11

What are the allotropes of Carbon?

Answer 11

1. Diamond
2. Graphite
3. Graphene
4. Fullerenes

Question 12

Why is graphite a good lubricant?

Answer 12

1. No covalent bond between layers
2. So they’re only held together weakly
3. So they can move over each other freely which makes it slippery.

Question 13

What is graphene?

Answer 13

1 layer of graphite

Question 14

Why is graphene useful to improve strength, and be used in electronics?

Answer 14

1. Network of covalent bonds makes it very strong and it is light
2. Because it has delocalised electrons it can conduct electricity.

Question 15

What are fullerenes?

Answer 15

Molecules of carbon shaped like closed tubes or hollow balls.

Question 16

What are the properties of nanotubes?

Answer 16

1.ratio between length and diameter is high
2.good conductor
3.high tensile strength

Question 17

Explain the structure of metallic bonding?

Answer 17

1. Electrons in outer shell are delocalised
2. There is a strong force of electrostatic attraction between the positive metal ions, and the sea of electrons
3. This holds the metal together in a strong, regular structure

Question 18

Why are metals solids at room temp?

Answer 18

1.The electrostatic forces of attraction between the metal ions and the sea of delocalised electrons are strong, and require lots of energy to overcome.

Question 19

Why are alloys harder?

Answer 19

1. When another element is mixed with a pure metal, the new different sized atoms distort the regular layers
2. This makes it harder to slide across eachother.

Question 20

How large are coarse particles, fine particles and nano particles?

Answer 20

Diameter of:
1.2500nm-10000nm
2. 100nm-2500nm
3. 1nm-100nm

Question 21

What are the uses of nanoparticles?

Answer 21

1.Catalysts
2.Nanomedicine
3.electric circuits
4.Anti-bacterials
5.Cosmetics

Question 22

What shape is a buckminster fullerene?

Answer 22

A Hollow sphere

Question 23

What can fullerenes be used for?

Answer 23

Transport medicine around the body.