chemistry - structure and bonding

Question 1

What are the three types of bond?

Answer 1

Covalent, ionic and metallic

Question 2

What happens to the electrons in an ionic bond?

Answer 2

They are transferred

Question 3

If an atom has gained electrons, what charge will it have as an ion?

Answer 3

Negative

Question 4

If an atom has lost electrons, what charge will it have as an ion?

Answer 4

Positive

Question 5

What type of elements will form ionic bonds?

Answer 5

Metal + non-metal

Answer 6

What is the charge on elements in group one and in group two?

Question 7

What is the charge on elements in group one and in group two?

Answer 7

Group 1: 1+

Group 2: 2+

Question 8

What is the charge on elements in group six and in group seven?

Answer 8

Group 6: 2-
Group 7: 1-

Question 9

Describe the structure and bonding in an ionic compound

Answer 9

Giant ionic lattice held together by strong electrostatic force of attraction between positive and negative ions

Question 10

State the melting point and boiling point of ionic compounds

Answer 10

High

Question 11

Explain the melting and boiling point of ionic compounds

Answer 11

High due to strong electrostatic forces of attraction which require lots of energy to break

Question 12

Explain why ionic compounds do not conduct electricity when solid

Answer 12

The ions are not free to move and carry a charge

Question 13

Explain why ionic compounds conduct electricity when molten or in solution

Answer 13

The ions are free to move and carry a charge

Question 14

What happens to the electrons in a covalent bond?

Answer 14

They are shared

Question 15

a
What type of elements will form covalent bonds?

Answer 15

Non-metals

Question 16

What type of substances have covalent bonds?

Answer 16

Giant covalent substances and small molecules

Question 17

How many bonds does each carbon have in diamond?

Answer 17

4

Question 18

Explain why diamond and silicon dioxide have high melting points

Answer 18

Giant structures, strong covalent bonds between the atoms, requires a lot of energy to break

Question 19

Explain why most covalent substances do not conduct electricity

Answer 19

There are no free electrons or ions that are free to move and carry a charge

Question 20

Making full reference to structure and bonding in graphite, explain how it conducts electricity

Answer 20

Each carbon has 3 bonds, 1 electron per carbon is delocalised and therefore free to carry a charge through the graphite

Question 21

Explain why graphite can act as a lubricant

Answer 21

Weak forces between layers which are free to slide over each other

Question 22

What type of substances are methane and water?

Answer 22

Small molecules

Question 23

Describe the structure of small molecules

Answer 23

Strong covalent bonds between atoms, weak intermolecular forces holding the molecules together

Question 24

Explain why small molecules have low melting points

Answer 24

It is a simple molecular substance with weak intermolecular forces which are easy to break

Question 25

Why do larger molecules have higher melting points than smaller ones?

Answer 25

Intermolecular force strengths with increased molecular size

Question 26

What is graphene?

Answer 26

One layer of graphite

Question 27

What is graphene used for?

Answer 27

Electronics and composite materials

Answer 28

27

Answer 29

What is a fullerene?

Answer 30

Substance made of carbon atoms arranged in a cage

Answer 31

28

Question 32

Describe the main features of metals in terms of their structure

Answer 32

Positive metal ions arranged in layers with delocalised electrons

Question 33

Explain why metals can conduct electricity

Answer 33

Delocalised electrons are free to carry charge through the metal

Question 34

Explain why pure metals are soft

Answer 34

Layers of metal ions are free to slide over each other

Question 35

what is an alloy

Answer 35

A mixture of two or more elements, at least one of which is a metal

Question 36

Give a reason for alloying a metal

Answer 36

To make it harder, to make it less reactive

Question 37

Explain why alloys can be harder than pure metals

Answer 37

Different size of atoms disturb the layers to stop them sliding over each other

Question 38

How many carats in pure metal

Answer 38

24 carat

Question 39

What are nanoparticles?

Answer 39

Particles that are 1-100 nm in size

Question 40

Why are nanoparticles useful?

Answer 40

Due to their high surface area to volume ratio

Question 41

What are nanotubes?

Answer 41

Cylindrical fullerenes

Question 42

What are nanotubes used for?

Answer 42

Electronics, nanotechnology and materials.