Bonding, Structure and Properties of Matter

Question 1

What are the three types of strong chemical bonds?

Answer 1

• Ionic bonds
• Covalent bonds
• Metallic bonds

Question 2

What is an ion?
Where do ionic bonds occur?

Answer 2

Atoms that have gained or lost electrons
Between positive and negative ions

Question 3

Do ions have an overall charge?

Answer 3

Yes

Question 4

What do ions have the same electronic structure as?

Answer 4

Noble gas - complete outer shell of electrons

Question 5

What does ionic bonding involve?

Answer 5

The transfer of electrons from metal atoms to non-metal atoms

Question 6

Describe what the charge of metal and non-metal atoms when they react to become ions.

Answer 6

Metals = lose electrons and become positively charged
Non-metals = gain electrons and become negatively charged

Question 7

What is an ionic bond?

Answer 7

A strong electrostatic force of attraction between the positive metal ion and the negative non-metal ion

Question 8

Practice question:
Describe what happens when two sodium atoms react with one molecule of chlorine.
Sodium has 1electron in outer shell
Chlorine has 7 electrons in outer shell

Answer 8

One chlorine molecule = 2 chlorine atoms
Sodium atom transfers one electron to one of chlorine atoms
All now have 8 electrons in outer shell
Become Na+ and Cl-
2Na + Cl2 —— 2NaCl

Question 9

What are ionic compounds?

Answer 9

Giant structures of ions

Question 10

What are ionic compounds held together by?

Answer 10

Strong forces of attraction (electrostatic forces) that act in all directions between oppositely charged ions

Question 11

Name some properties of ionic compounds.

Answer 11

• High melting points
• Do NOT conduct electricity when solid because ions cannot move
• Do conduct electricity when molten or in solution because the charged ions are free to move about and carry their charge

Question 12

Why do metals form positively charged ions?

Answer 12

Because they lose electrons in order to form ions

Question 13

Why do ionic compounds have high melting and boiling points?

Answer 13

Ionic bonds are very strong and therefore requires a lot of energy to overcome them

Question 14

Where does metallic bonding occur?

Answer 14

In metallic elements such as iron and copper
Alloys such as stainless steel

Question 15

Describe the structure of metals.

Answer 15

A giant 3D lattice in which electrons in the outer shell are delocalised

Question 16

What is a metallic bond?

Answer 16

The attraction between the positive ions and the delocalised negatively charged electrons

Question 17

Why are metals good thermal and electrical conductors?

Answer 17

The delocalised electrons can move freely and transfer energy

Question 18

Why do most metals have high melting and boiling points?

Answer 18

Metallic bonds are very strong meaning that a lot of energy is required to break them

Question 19

Why can metals be bent and hammered into different shapes?

Answer 19

The layers are able to slide over each other quite easily

Question 20

Practice question:
Why is copper used to make water pipes?

Answer 20

• It’s an interactive metal, so it does not react with water
• It can be easily shaped

Question 21

What is an alloy?

Answer 21

Mixtures that contain a metal and at least one other element

Question 22

Why are pure metals rarely used?

Answer 22

They are to soft

Question 23

In alloys, what does the added element do to the arrangement of the metal atoms?

Answer 23

It disturbs the regular arrangement so the layers do not slide over each other so easily

Question 24

What is steel?

Answer 24

A very useful alloy made from iron

Question 25

When iron oxide is reduced in a blast furnace what does this produce?

Answer 25

Iron

Question 26

What does molten iron, obtained from a blast furnace, contain?

Answer 26

Approx. 96% iron and 4% impurities l, including carbon phosphorus and silica

Question 27

Why is iron brittle when obtained from a blast furnace?

Answer 27

It’s impure

Question 28

How are the atoms in pure iron arranged?

Answer 28

In layers that can slide over one another easily making it soft and malleable

Question 29

Name some properties of steel depending on the amount of carbon/ other elements.

Answer 29

- Steel with a high carbon content is hard and strong - Steel with a low carbon content is soft and easily shaped - Stainless steel contains chromium and nickel and is hard and resistant to corrosion

Question 30

What is a covalent bond?

Answer 30

A shared pair of electrons between atoms

Question 31

Where do covalent bonds occur (what type of elements)?

Answer 31

- Non-metallic elements e.g. oxygen - Compounds of non-metals e.g. sulfur dioxide

Question 32

Example question: A chlorine atom has seven electrons in its outer shell. In order to bond with another chlorine atom what occurs?

Answer 32

- An electron from each atom is shared - This gives each chlorine atom eight electrons in the outer shell - Each atom now has a complete outer shell

Question 33

Are covalent bonds strong or weak?

Answer 33

Strong

Question 34

What do simple molecules contain?

Answer 34

A relatively small number of non-metal atoms joined together by covalent bonds

Question 35

Why do simple molecular substances (e.g. water) have low melting and boiling points?

Answer 35

There are weak forces of attraction between the molecules which are easily overcome

Question 36

Do simple molecular substances conduct electricity? Why?

Answer 36

No, they have no overall electrical charge

Question 37

Key point:

Answer 37

The intermolecular forces between simple molecules are very weak compared to the strength of covalent bonds in the molecules themselves

Question 38

How does the size of molecules relate to the strength of the intermolecular forces between simple molecules?

Answer 38

The larger the molecules are the stronger the intermolecular forces between simple molecules become. This means larger molecules have higher melting and boiling points

Question 39

How does differ in Group 7 of the periodic table?

Answer 39

The molecules get larger as you go down and so the melting and boiling points also increase

Question 40

What are all the atoms in giant covalent structures linked by?

Answer 40

Strong covalent bonds

Question 41

What are giant covalent structures?

Answer 41

Solids with very high melting and boiling points

Question 42

What is diamond?

Answer 42

A form of carbon

Question 43

Name some features of diamond?

Answer 43

- It has a giant, rigid covalent structure (lattice) - Each carbon atom forms four strong covalent bonds with other carbon atoms - All the strong covalent bonds mean that it is a very hard with a very high melting point - There are no charged particles, so it does not conduct electricity

Question 44

What is graphite?

Answer 44

A form of carbon

Question 45

What structure does graphite have?

Answer 45

Giant covalent structure

Question 46

Does graphite have a high or low melting point?

Answer 46

High

Question 47

What does each carbon atom form?

Answer 47

Three covalent bonds with other carbon atoms

Question 48

Describe the structure of graphite.

Answer 48

A layered, hexagonal structure

Question 49

What are the layers in graphite held together by? What does this mean?

Answer 49

Weak intermolecular forces. This means that the layers can slide last each other, making graphite soft and slippery

Question 50

One electron from each carbon atom in graphite is delocalised. What does this allow graphite to do?

Answer 50

Conduct heat and electricity

Question 51

Describe the structure of silicon dioxide.

Answer 51

Giant covalent structure and has lattice structure similar to diamond

Question 52

In silicon dioxide what is each oxygen atom joined too?

Answer 52

Two silicon atoms

Question 53

In silicon dioxide what is each silicon atom joined too?

Answer 53

Four oxygen atoms

Question 54

What is graphene?

Answer 54

A form of carbon A single layer of graphite

Question 55

How are the atoms in graphene arranged?

Answer 55

In a hexagonal structure, just one atom thick

Question 56

Name some of graphene’s properties.

Answer 56

V. strong Good thermal and electrical conductor Nearly transparent

Question 57

What is graphene useful for?

Answer 57

In electronics and composite materials

Question 58

What else can carbon form?

Answer 58

Fullerenes - these contain different numbers of carbon atoms

Question 59

Describe the structure of fullerenes.

Answer 59

Hexagonal rings of carbon atoms

Question 60

Describe what buckminsterfullerene is.

Answer 60

-The first fullerene discovered -Consists of 60 carbon atoms joined together in a series of hexagons and pentagons

Question 61

What are carbon nanotubes?

Answer 61

Cylindrical fullerenes with very high length diameter ratios

Question 62

What are sone of the things carbon nanotubes are useful for?

Answer 62

- Nanotechnology - Electronics - Reinforcing materials - To deliver drugs in the body - As catalysts

Question 63

What do polymers consist of?

Answer 63

Very large molecules

Question 64

What are plastics?

Answer 64

Synthetic polymers

Question 65

What are the atoms within polymers held together by?

Answer 65

Strong covalent bonds

Question 66

Are the intermolecular forces between large polymer molecules strong or weak?

Answer 66

Strong

Question 67

What state of matter are polymers at room temperature?

Answer 67

Solids

Question 68

How is polythene (Poly(ethene)) produced?

Answer 68

When lots of theme molecules are joined together in an addition polymerisation reaction

Question 69

How many atoms do nanoparticles contain?

Answer 69

A few hundred