Structures and Properties

Question 1

When does ionic bonding occur

Answer 1

When a metal and a non-metal react together

Question 2

How does an ionic bond form

Answer 2

The metal (magnesium) loses (2) electrons and become cations
The nonmetal (chlorine) each gain one electron and become anions so they all have full outer shell
The positive ions are attracted to the negative ions and have an electrostatic attraction between them

Question 3

Describe the bonding in an ionic compound

Answer 3

There is an electrostatic attraction between oppositely charged ions

Question 4

When can ionic compounds conduct electricity? Why?

Answer 4

When they are molten or in an aqueous solution

The ions are free to move to their oppositely charged electrode and carry a charge

Question 5

When can ionic compounds not conduct electricity and why

Answer 5

When they are solid
The ions are fixed in a giant lattice so the ions are not free to move to their oppositely charged electrode and carry a charge

Question 6

Do ionic compounds have high or low boiling points, justify your answer

Answer 6

They have high boiling points because there are millions of strong electrostatic attractions between oppositely charged ions in the giant lattice which require a lot of heat energy to break them

Question 7

Can ionic compounds be dissolved in water, justify your answer

Answer 7

Yes they can, water is a polar molecule which can break up the ionic lattice

Question 8

Describe the structure of an ionic compound

Answer 8

A giant lattice that extends in all directions

Question 9

Why are ionic compounds solid at room temperature

Answer 9

They have a high melting point as there are millions of strong electrostatic attraction between the ions in the giant lattice that take a lot of energy to break

Question 10

Examples of simple molecules

Answer 10

Water, methane, carbon dioxide

Question 11

Do simple molecules have high or low melting points, why

Answer 11

There are weak intermolecular forces between the molecules that take little energy to break up

Question 12

Why do simple molecules not conduct electricity

Answer 12

There is no overall charge on the simple molecules so their neutral and therefore cant carry an electrical charge

Question 13

Describe the bonding of a covalent molecule

Answer 13

There are strong covalent bonds between the atoms

Question 14

Why do diamonds have high melting points

Answer 14

Diamonds have a macro molecular structure. There are millions of carbon atoms held by strong covalent bonds

Question 15

Why might diamonds be used drill bits

Answer 15

They are real hard
Diamonds have a macro molecular structure. There are millions of carbon atoms held by strong covalent bonds so have a rigid structure

Question 16

Why can’t diamonds conduct electricity

Answer 16

Each carbon atom is bonded to 4 other carbon atoms by strong covalent bonds so there are no delocalised electrons that can conduct electricity

Question 17

Why does graphite have a high melting point

Answer 17

It has a macro molecular structure. Within each layer, each carbon atom us joined to 3 other carbon atoms by strong covalent bonds which take a lot of energy to break

Question 18

Why can graphite conduct electricity

Answer 18

Within each layer of the structure, each carbon atom is joined by 3 other carbon atoms by strong covalent bonds. Therefore it has delocalised electrons which can carry charge through the structure and conduct electricity

Question 19

Why is graphite soft

Answer 19

Graphite has a macro molecular structure which consists of layers. Each layer consists of millions of carbon atoms arranged in hexagons. Between the layers are weak intermolecular forces which can easily slide over each other making it very soft

Question 20

What are fullerenes and potential uses

Answer 20

Large carbon molecules which have cage-like structures of different shapes. Can be used for drug delivery to specific parts of the body

Question 21

What does aq mean

Answer 21

Aqueous - dissolved in water

Question 22

What is the meaning of “nanowire”

Answer 22

Very small size

Question 23

Nanoparticles are tiny… What does this mean

Answer 23

Have a high surface area to volume ratio

Question 24

What is the structure of metals

Answer 24

Lattice - giant metallic structure arranged in closely packed regular layers

Question 25

How do metallic bonds form

Answer 25

The electrons on the outer shell are donated to the “sea” of delocalised electrons which surround the positive metal ions. There is a strong electrostatic attraction between positive ions and negative electrons

Question 26

Why can metals conduct electricity and heat

Answer 26

The electrons on the outer shell are donated to the sea of electrons that are free to move and therefore are able to conduct electricity and heat

Question 27

Why are metals malleable and ductile

Answer 27

The atoms in pure metals can easily slide over each other

Question 28

How can we make metals stronger

Answer 28

Alloys - mix metals with other metals so the other atoms distort the layers and make it harder to slide over one another

Question 29

Why do metals have a high melting point

Answer 29

There are millions of strong electrostatic attractions between the positive ions and negative electrons that take a lot of energy to break them

Question 30

Why might aluminium have a higher melting point than sodium

Answer 30

Aluminium forms a 3+ ion because it loses 3 electrons whereas sodium forms 1+ ions as it is in group 1, therefore aluminium has stronger metallic bonds

Question 31

Why might magnesium be a better conductor than sodium

Answer 31

Each magnesium atom loses 2 electrons into the “sea” whereas sodium only loses 1 so there are more delocalised electrons in magnesium to carry a charge

Question 32

Why can silver stop unpleasant smells when wearing no socks

Answer 32

Silver has a special property that can kill bacteria

Question 33

Why might nanoparticles be dangerous

Answer 33

Their large surface area could make them dangerous as too effective catalysts so may cause a spark or violent explosion