C2: Bonding

Question 1

How do metal atoms bond to each other?

Answer 1

-Metallic bonding
-Form a lattice of positive ions
-Surrounded by a ‘sea’ of delocalised electrons

Question 2

Why do metals make good conductors?

Answer 2

Electrons are free to move

Question 3

How do metals bond to non-metals?

Answer 3

-Ionic bonding
-Metal atoms donate electrons to non-metals to form ions

Question 4

How do we show the electrons on the outer shells in ionic bonding?

Answer 4

-Dot and cross diagrams
-Metals always end up with an empty outer shell
Non-metals always end up with a full outer shell

Question 5

What must the charges of all ions in an ionic compound add up to?

Answer 5

Zero

Question 6

How are ions arranged?

Answer 6

-In a lattice of repeating units of positive and negative ions
-These form a crystal

Question 7

What are characteristics or ionic substances?

Answer 7

-High melting/boiling points
-Due to strong ionic bonds
-Ions have strong electrostatic forces between them

Question 8

Can ionic structures conduct electricity?

Answer 8

-Yes, when molten or in a solution (dissolved)
-Ions are free to move in these states so can carry charge

Question 9

What are examples of molecular ions?

Answer 9

-Hydroxide ions: OH-
-Sulphate ions: SO2-
-Carbonate ions: CO2-
-Nitrate ions: NO-
-Ammonium ions: NH+

Question 10

What is a molecular ion?

Answer 10

A particle made of one or more atom with an overall positive or negative charge

Question 11

What can ionic compounds also be called?

Answer 11

Salts e.g. sodium chloride

Question 12

What are positive ions also know as?

Answer 12

Cations

Question 13

What are negative ions also known as?

Answer 13

Anions

Question 14

How do non-metals bond to each other?

Answer 14

By covalent bonding

Question 15

What is covalent bonding?

Answer 15

-Atoms share electrons to gain full outer shells
-Every covalent bond consists of a pair of shared electrons

Question 16

What does the dot & cross diagram look like for covalent bonding?

Answer 16

Dots and crosses in the middle of the overlapping atoms

Question 17

What determines the number of bonds an atom makes?

Answer 17

The number of electrons an atom needs

Question 18

What are simple covalent structures?

Answer 18

Molecules with a small number of atoms covalently bonded

Question 19

What are characteristics of covalently bonded molecules?

Answer 19

-Low melting/boiling points
-Due to weak intermolecular forces
-Take little energy to overcome

Question 20

What are giant covalent structures?

Answer 20

Structures that consist of repeating units of atoms to make what are essentially giant molecules

Question 21

What are examples of giant covalent structures?

Answer 21

-Diamond
-Silicon dioxide (‘silica’)
-Graphite

Question 22

What are properties of diamond?

Answer 22

-Very hard
-Strong bonds
-Very high melting and boiling points

Question 24

Where are properties of graphite?

Answer 24

-Soft and slippery (layers can slide past each other)
-Due to weak bonds between layers
-Can conduct electricity
-Due to delocalised electrons

Question 25

What are alloys?

Answer 25

Mixtures of metals

Question 26

What are properties of metal alloys?

Answer 26

-Strong
-Layers cannot slide over each other easily
-Due to different sized atoms disrupting the layers

Question 27

What is graphene?

Answer 27

A single layer of graphite

Question 28

What can fullerenes/nanotubes be used for?

Answer 28

-Electronics
-Composites
-Medical purposes

Question 29

What is a spherical fullerene?

Answer 29

Buckminster fullerene (60 carbons)

Question 30

How big are nano particles?

Answer 30

100-2500nm

Question 31

How big are coarse particles e.g. dust?

Answer 31

> 2500nm

Question 32

What happens when to the surface to volume ratio when the length of the side of a cube doubles?

Answer 32

It is halved

Question 33

Why are fullerenes useful?

Answer 33

They have a high surface to volume ratio