4.6.2 Structure and Bonding

Question 1

What are the three different types of bonding?

Answer 1

Ionic, covalent and metallic

Question 2

When does ionic bonding occur?

Answer 2

Ionic bonding is between a metal and a non metal.

Question 3

When does covalent bonding occur?

Answer 3

Covalent bonding occurs between non metals.

Question 4

When does metallic bonding occur?

Answer 4

Metallic bonding occurs between metals and mixtures of metals in alloys.

Question 5

What happens in covalent bonding?

Answer 5

Elements share pairs of electrons.

Question 6

What happens during ionic bonding?

Answer 6

Metal elements donate electrons to non metals. This forms positive and negative ions, which are attracted to each other.

Question 7

What happens during metallic bonding?

Answer 7

Each metal atom delocalises the electrons in the outer shell. This gives positive metal ions, surrounded by a sea of delocalised electrons

Question 8

What charge will an ion be if it loses an electron?

Answer 8

Positive - as electrons are negative

Question 9

What charge will an ion be if it gains two electrons?

Answer 9

2 negative- as it has gained 2 negative electrons

Question 10

Which types of elements generally lose electrons? Why?

Answer 10

Metals - because they have less than 4 electrons in their outer shell.

Question 11

Which types of elements generally gain electrons? Why?

Answer 11

Non -metals - because they have 4 or more electrons in their outer shell.

Question 12

What is an ionic bond?

Answer 12

The electrostatic attraction between oppositely charged ions.

Question 13

How would you describe the STRUCTURE of an ionic compound? Why?

Answer 13

Giant! It is made up of lots and lots of oppositely charged ions.

Question 14

Why can an ionic compound not conduct electricity when it is solid?

Answer 14

In a solid particles are fixed in one place.

The IONS cannot move around.

Question 15

How can you make salt conduct electricity?

Answer 15

Melt it or dissolve it in water

Question 16

Why do ionic compounds conduct electricity when they are dissolved in water or melted?

Answer 16

Ions are free to move around in a liquid. They can then carry the electrical charge through the liquid.

Question 17

Why do ionic substances, like salt, have high melting points?

Answer 17

The oppositely charge ions are very strongly attracted to each other. This means a lot of heat energy is needed to break this attraction.

Question 18

How would you describe the STRUCTURE of simple covalent structures like water and carbon dioxide.

Answer 18

They are SIMPLE structures as they are only made of a few atoms bonded together.

Question 19

What properties do simple covalent structures, like water and carbon dioxide, have?

Answer 19

Low melting point (as they are already a liquid and a gas!) and they do not conduct electricity.

Question 20

Why do simple covalent structures have low melting points?

Answer 20

When simple covalent structures melt it is a WEAK INTERMOLECULAR FORCE between the compounds that is broken. This only needs a SMALL amount of heat energy to be broken.

Question 21

Why do simple covalent structures not conduct electricity?

Answer 21

There are no free electrons or ions, so nothing can carry the electrical charge.

Question 22

What are the names of the two GIANT covalent structures made from CARBON.

Answer 22

Diamond and Graphite

Question 23

How many bonds are there between Carbon atoms in diamond?

Answer 23

4

Question 24

How many bonds are there between Carbon atoms in graphite.

Answer 24

3 - leaving one free electron.

Question 25

Why do giant covalent structures, like diamond and graphite, have high melting points?

Answer 25

Lots of strong covalent bonds have to be broken to melt these compounds.

Question 26

Why does diamond not conduct electricity, but graphite does?

Answer 26

All of the electrons in carbon are involved in bonding for diamond.

In graphite each Carbon has one free electron. This electron can move through the graphite structure carrying the electrical charge.

Question 27

Why is diamond strong and hard?

Answer 27

It is made of lots of strong covalent bonds in a structure.

Question 28

Why is graphite soft?

Answer 28

Graphite is arranged in layers. It has strong covalent bonds within the layers, but no bonds between the layer.

The attraction between the layers is weak, so the layers can slide over each other.

Question 29

How would you describe the STRUCTURE of a metal?

Answer 29

GIANT! It is made of lots and lots of metal ions.

Question 30

Why do metals have high melting points?

Answer 30

There is a strong attraction between the metal ions and delocalised electrons in a metal. This means it needs a lot of energy to break this attraction and melt the metal.

Question 31

Why do metals conduct electricity?

Answer 31

Metals have free electrons. These electrons move through the metal carrying the electrical charge.

Question 32

Why do metals conduct heat?

Answer 32

The delocalised electrons near the heat source gain kinetic energy. As they move through the metal they bang into the metal ions and pass on this kinetic energy.

Question 33

What is an alloy?

Answer 33

A mixture of a metal with another metal.

Question 34

How are alloys (like steel and brass) better than the metals they are made from (iron and copper)?

Answer 34

They are stronger (less malleable).

This is because an alloy is not arranged in layers, the different sized particles distort the layer. This means the metal ions do not slide over each other.

Question 35

Why are metals malleable?

Answer 35

The metal ions are arranged in layers which can slide easily over each other.