Structure and bonding

Question 1

What is ionic bonding?

Answer 1

A strong electrostatic attraction between the positive and negative ions.

Question 2

Where does ionic bonding occur?

Answer 2

It occurs between a metal and a non-metal.

Question 3

What structure does an ion make?

Answer 3

An alternating structure where each ion is surrounded by ions of the opposite charge.
An ionic lattice.

Question 4

Overall the ionic compound is ________.

Answer 4

Neutral.

Question 5

The formula which shows the ratio between the ions is called the ________.

Answer 5

Empiricle formula or Ionic Formula.

Question 6

Properties of Ionic Compounds:

Answer 6

Hard, Brittle
High melting and boiling point (solid at room temp)
Conducts electricity when in a solution

Question 7

Give the ionic formula for: Potassium iodide

Answer 7

KI

Question 8

Give the ionic formula for: Barium Chloride

Answer 8

BaCl2

Question 9

Give the ionic formula: Copper Oxide

Answer 9

Cu2O2 = CuO

Question 10

Give the ionic formula for: Aluminium sulphide

Answer 10

Al2S3

Question 11

Give the ionic formula for: Calcium Sulphate

Answer 11

CaSo4

Question 12

Where does covalent bonding occur?

Answer 12

In non-metal elements and compounds.

Question 13

What happens to electrons in covalent bonding?

Answer 13

They share electrons to get full outer shells.

Each pair is a single covalent bond.

Question 14

Drawing covalent compound rules:

Answer 14

The outer shell should overlap and the shared pair of electrons should be inside the overlap bit.
Only draw the outer shell.
Use dots and crosses to show where the electron originated.

Question 15

Compound for Sulphate:

Answer 15

SO4 (charge -2)

Question 16

Compound for Nitrate:

Answer 16

NO3 (charge -)

Question 17

Compound for Hydroxide:

Answer 17

OH (charge -)

Question 18

Compound for Carbonate:

Answer 18

CO3 (charge -2)

Question 19

Ways to draw Covalent bonds:

Answer 19

Dot Cross diagram

Line diagram

Question 20

What are covalent molecules and their properties?

Answer 20

1. They have low melting and boiling points - they are gases or liquids at room temperature.
2. The bigger the molecules the stronger the forces, so melting and boiling points increase with size.
3. Simple covalent molecules have no overall charge therefore can’t conduct electricity.

Question 21

Silicon dioxide:

Answer 21

Large number of strong covalent bonds
High melting and boiling points
Hard Crystalline structure
No charged particles so can’t conduct electricity

Question 22

Polymers:

Answer 22

Large molecules made up of repeating units bonded together as long chains
They are represented by showing the individual unit (monomer) and ‘n’ to represent a large number
e.g. poly (ethane)
The don’t conduct electricity

Question 23

Diamond;

Answer 23

Tetrahedral
Each Carbon connected to 4 others
Very hard
High melting and boiling points
Don’t conduct electricity as there are no delocalised electrons
Use them as jewels and for cutting stuff as it is really hard.

Question 24

What is a delocalised electron?

Answer 24

An electron that can wander around.

Question 25

Graphite:

Answer 25

``` Hexagonal structure with many layers. Quite soft as layers can slide. High melting and boiling point Conducts electricity as there is one delocalised electron from each carbon, free to move. Uses: Lubricant, Pencils ```

Question 26

Fullerenes:

Answer 26

``` 60 Carbon atoms joined together To form a ball/tube Other forms exist like carbon nanotubes They Conduct electricity as they have delocalised electrons. Strong High melting and boiling points They can be used for drug delivery. ```

Question 27

Graphene:

Answer 27

A single layer of graphite It is used in composite materials because the covalent bonds within the layer makes it very strong but flexible as it is so thin It can conduct electricity.

Question 28

Compound for Ammonium:

Answer 28

NH4 (charge +)

Question 29

Metals have _____.

Answer 29

Layers.

Question 30

What is the structure of a giant metallic lattice?

Answer 30

Electrons from outer shells of metal atoms are free to move. | Positive metal ions

Question 31

Metal atoms ____ outer electrons.

Answer 31

Metal atoms LOSE outer electrons.

Question 32

Metal atoms become ________ ions.

Answer 32

Metal atoms become POSITIVE ions.

Question 33

Free electrons are called ___________ electrons.

Answer 33

Free electrons are called DELOCALISED electrons.

Question 34

The delocalised electrons are ____ to ____ throughout the metallic structure.

Answer 34

The delocalised electrons are FREE to MOVE throughout the metallic structure.

Question 35

There is a strong force of attraction between the _________ ions and the ________ electrons. This is called the _____________ force of __________. This force is very ______ in metals.

Answer 35

There is a strong force of attraction between the POSITIVE ions and the NEGATIVE electrons. This is called the ELECTROSTATIC force of ATTRACTION. This force is very STRONG in metals.

Question 36

Metallic properties because of delocalised electrons:

Answer 36

Can conduct heat and electricity

Question 37

Metallic properties because of layers of metal ions which can slip over each other:

Answer 37

Malleable (Can be shaped) | Ductile (Can be stretched into wires)

Question 38

Metallic properties because of the strong force of attraction between the metal ion and the delocalised electron:

Answer 38

Hard High melting and boiling point (except mercury - Hg) Solid at room temperature (except mercury - Hg)

Question 39

What is an alloy?

Answer 39

Mixtures of metals or of a metal and a carbon.

Question 40

Properties of an alloy in comparison to the metals they contain:

Answer 40

They are stronger, harder , less malleable and less ductile than the metals they contain.

Question 41

What do alloys disrupt?

Answer 41

They disrupt the layers, making it harder for them to slide over each other. This is because the atoms are different sizes.

Question 42

Ionic bonding and covalent bonding gives them the structure of :

Answer 42

A noble gas. This makes them very stable.

Question 43

How do you work out the ratio of surface area to volume ratio:

Answer 43

surface area / volume

Question 44

Nanoparticle diameter :

Answer 44

``` Between 1nm (1 x 10 to the power of -9 m) and 100nm (1 x 10 to the power of -7 m) These are particles containing only a few hundred atoms. ```

Question 45

The surface area of a nanoparticle is very _____ in comparison to the ______.

Answer 45

The surface area of a nanoparticle is very LARGE in comparison to the VOLUME.

Question 46

Because nanoparticles have a huge surface area to volume ratio, they could help to make ___ _________.

Answer 46

Because nanoparticles have a huge surface area to volume ratio, they could help to make new catalysts.

Question 47

Nanomedicine:

Answer 47

Tiny particles (such as fullerenes) are absorbed more easily by the body than most particles. This means the could deliver drugs right into the cells where they are needed.

Question 48

Silver nanoparticles:

Answer 48

They have antibacterial properties. They can be added to polymer fibres that are then used to make surgical masks and wound dressings.

Question 49

Nanoparticles in sun creams:

Answer 49

They have been shown to be better at protecting skin from harmful UV rays and give better skin coverage compared to traditional sun creams. It is unclear if they may damage cells and there is a possibility it may damage the environment when washed away.