2. Structure and bonding

Question 1

State what the types of bonding exist between atoms in terms of metals and non-metals

Answer 1

Ionic = metals and non-metals
Covalent = non-metals only
Metallic = metals only

Question 2

What happens to the electrons in each type of bonding?

Answer 2

Ionic = transferred from metal to non-metal
Covalent = shared
Metallic = forms a sea of delocalised electrons

Question 3

What structure do ionic compounds form?

Answer 3

Giant ionic lattice

Question 4

Explain why ionic substances have high melting points.

Answer 4

Strong bonds between oppositely charged ions are hard to break

Question 5

Explain why ionic compounds do not conduct electricity when solid

Answer 5

Because the ions are not free to move

Question 6

Explain why ionic compounds conduct electricity when molten or in solution

Answer 6

Because the ions are free to move

Question 7

What two structures do covalent compounds form?

Answer 7

Simple molecular and giant covalent lattice

Question 8

What are five examples of giant covalent structures?

Answer 8

Diamond, silicon dioxide, graphite, graphene, fullerenes

Question 9

Explain why giant covalent structures have a high melting point

Answer 9

Giant structure, Strong covalent bonds between the atoms, requires a lot of energy to break

Question 10

Explain why most giant covalent substances do not conduct electricity

Answer 10

There are no electrons/ions/charged particles that are free to move

Question 11

Explain why graphite conducts electricity

Answer 11

Has delocalised electrons between the layers that can move through the graphite

Question 12

Explain why graphite can act as a lubricant

Answer 12

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

Question 13

What are intermolecular forces?

Answer 13

Weak forces between molecules which hold them together

Question 14

Explain why simple molecules have a low melting point

Answer 14

It is a simple molecular substance with weak forces between the molecules (which are easy to break)

Question 15

What is a polymer?

Answer 15

Millions of small molecules joined together in a chain to form a large molecule

Question 16

What structure do metallic compounds form?

Answer 16

Giant metallic lattice

Question 17

Explain why metals can conduct electricity

Answer 17

Delocalised electrons are free to carry charge through the whole structure

Question 18

Explain why pure metals are soft

Answer 18

Layers of metal ions are free to slide over each other

Question 19

Give a reason for alloying a metal

Answer 19

To make it harder, to make it less reactive

Question 20

Explain why alloys can be harder than pure metals

Answer 20

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