Ionic Bonding and Electrolysis

Question 1

What is an ion?

Answer 1

A charged particle

Question 2

What do atoms try to achieve when reacting?

Answer 2

A full outer shell of electrons/ stable electronic structure

Question 3

What are positive ions called?

Answer 3

Cations

Question 4

What are negative ions called?

Answer 4

Anions

Question 5

Where does ionic bonding take place?

Answer 5

Between a non-metal and a metal

Question 6

What happens in the ionic bonding process?

Answer 6

Metal atom transfers electrons (to get stable electronic structure) to form a positive ion and non-metal gains them to form a negative ion.

Question 7

What does an oxidation reaction involve?

Answer 7

A loss of electrons

Question 8

What does a reduction reaction involve?

Answer 8

A gain of electrons

Question 9

In terms of half equations, what type of reaction does a metal undergo in ionic bonding?

Answer 9

Oxidation

Question 10

In terms of half equations, what type of reaction does a non-metal undergo in ionic bonding?

Answer 10

Reduction

Question 11

What is a giant ionic crystal lattice structure?

Answer 11

A solid, regular arrangement of millions of ions where there are very strong electrostatic forces of attraction between oppositely charged ions, in all directions

Question 12

What are the properties of a Giant Ionic Structure?

Answer 12

• High melting points and boiling points
• Semi-conductors
• Can be brittle and not shatter proof

Question 13

What is the structural name of metal and non-metal compounds?

Answer 13

Giant ionic crystal lattice

Question 14

What type of diagram is used to show the arrangement of ions and/or atoms?

Answer 14

Dot and cross diagram

Question 15

What is the empirical formula?

Answer 15

A formula used to show the ratio if different elements in a compound

Question 16

Why do giant ionic crystal lattice structures have high melting and boiling points?

Answer 16

The structure has lots of strong ionic bonds which need a large amount of energy to overcome the attraction and break them

Question 17

Under which conditions do ionic compounds conduct electricity? Why?

Answer 17

• When molten: Ions are free to move and they’ll carry electric current
• When dissolved in water: The ions are separated and free to move in the solution so they’ll carry the electric current

Question 18

What are the two ways in which giant ionic lattices can be represented?

Answer 18

• Using a giant 3D giant ionic crystal lattice structure model
• Using the ball and stick giant ionic crystal lattice structure model

Question 19

What are the advantages of the giant 3D giant ionic crystal lattice structure model?

Answer 19

• It shows the regular arrangement of ions/regular pattern

- Shows the relative size of the ions

Question 20

What are the disadvantages of the giant 3D giant ionic crystal lattice structure model?

Answer 20

-You can only see the outer layer of the compound

Question 21

What are the advantages of the ball and stick giant ionic crystal lattice structure model?

Answer 21

• Shows the 3D regular arrangement of ions in the lattice

- Shows that the crystal extends beyond what is shown in the diagram

Question 22

What are the disadvantages of the ball and stick giant ionic crystal lattice structure model?

Answer 22

• May not show the relative size of the ions

- Shows gaps between ions when in reality, there are none

Question 23

Define electrolysis:

Answer 23

The splitting up of an ionic compound (into it’s elements) using electricity

Question 24

What is an electrolyte?

Answer 24

a mixture of ions which can conduct electricity

Question 25

What happens during electrolysis in principle?

Answer 25

An electric current is passed through an electrolyte. The ions in the electrolyte move towards the electrodes where they react and the compound decomposes

Question 26

To which electrode do the positive ions move towards during electrolysis?

Answer 26

The cathode (negative electrode)

Question 27

To which electrode do the negative ions move towards during electrolysis?

Answer 27

The anode (positive electrode)

Question 28

What occurs at the cathode during electrolysis?

Answer 28

The anions gain electrons from the cathode which has surplus electrons. They are reduced

Question 29

What occurs at the anode during electrolysis?

Answer 29

The cations lose lose electrons to the anode which is short of electrons. They are oxidised

Question 30

What happens as the ions gain or lose electrons at the electrodes during electrolysis?

Answer 30

They form the uncharged element and are discharged from the electrolyte

Question 31

What materials are electrodes made from?

Answer 31

- Metals such as Platinum as it is inert | - Graphite as it is cheap and a good conductor

Question 32

From which ore is aluminium extracted from by electrolysis?

Answer 32

Bauxite- contains aluminium oxide, Al2O3

Question 33

Aluminium oxide has a very high melting point (2000), what is it mixed with to reduce its melting point for electrolysis?

Answer 33

Cryolite - lowers melting point to around 950

Question 34

What happens to the positive aluminium ions once the electric current is passed through the electrolyte?

Answer 34

They are attracted to the cathode (negative) and pick up three electrons and turn into neutral aluminium atoms. These sink to the bottom of the electrolysis tank

Question 35

What happens to the negative oxygen ions once the electric current is passed through the electrolyte?

Answer 35

They are attracted to the anode (positive) and lose two electrons. The neutral oxygen atoms will then combine to form 02 molecules.

Question 36

Why does the carbon anode in the aluminium extraction process need to be replaced regularly?

Answer 36

Because it reacts with oxygen to produce carbon dioxide

Question 37

What are disadvantages of metal extraction from ores using electrolysis?

Answer 37

It is expensive (continues supply of electricity and heating costs) and enhances the greenhouse effect with the production of carbon dioxide

Question 38

What is the test for chlorine production?

Answer 38

-Chlorine bleaches blue litmus paper, turning it white

Question 39

What is the test for hydrogen production?

Answer 39

- Hydrogen will make a "squeaky pop" with a lighted splint

Question 40

What is the test for oxygen production?

Answer 40

-Oxygen will relight a glowing splint

Question 41

What ions are present in an aqueous solution which is ready for electrolysis?

Answer 41

``` Negative ions: -That of the dissolved ionic compound -Hydroxide Positive ions: -That of the dissolved ionic compound -Hydrogen ```

Question 42

What is produced at the cathode in an electrolysed aqueous solution?

Answer 42

That which is the least reactive

Question 43

What is produced at the anode in an electrolysed aqueous solution?

Answer 43

If a halide ion is present, then chlorine, bromine or iodine will be formed (halides). If no halide ions are present, then the hydroxide ions are discharged and oxygen and water will be formed

Question 44

What are delocalised electrons?

Answer 44

- Free electrons - which are not attached to a particular atom - and don't orbit an atom in an energy level

Question 45

What makes an ionic bond stronger?

Answer 45

The more electrons that are transferred, the stronger the forces of attraction

Question 46

What is an ionic bond?

Answer 46

the electrostatic attraction between oppositely charged ions acting in al directions

Question 47

Describe how an ionic bond forms between potassium and iodine?

Answer 47

- potassium transfers 1 electron to form a potassium metal cation - iodine gains the electron transferred by the potassium forming the non-metal anion - the positive and negative ions are held together by forces of electrostatic attraction between the oppositely charged ions acting in all directions

Question 48

what is a molten salt?

Answer 48

a compound that is melted using heat which separates it into its ions

Question 49

what is a dissolved salt?

Answer 49

a compound that is dissolved in water which separates it into its ions

Question 50

What is discharge?

Answer 50

the reaction which happens at electrodes where the elements or compounds are formed

Question 51

Why can a rechargeable cell be recharged?

Answer 51

Chemical reaction within the cell is reversible

Question 52

What makes something an alkaline fuel cell?

Answer 52

If it contains hydroxide ions