Oxford Revise AQA GCSE Combined Science Foundation | Chapter C3 answers

C3: Ionic bonding, metallic bonding, and structure

Question

Answers

Extra information

Mark

AO / Specification reference

01.1

transferred

1

AO1

5.2.1.2

01.2

metal – loses an electron

non-metal – gains an electron

1

AO1

5.2.1.2

01.3

electrostatic attraction

1

AO1

5.2.1.2

02.1

bottom answer

1

AO2

5.2.1.2

02.2

NaCl

1

AO2

5.2.1.3

02.3

high melting point/high boiling point/do not conduct electricity when solid/conduct electricity when molten/conduct electricity when dissolved in water/soluble in water

1

AO1

5.2.2.3

02.4

Level 3: The comparisons are detailed and accurate. The writing is clear, coherent and logical and comparisons are clearly made.

5–6

AO1

5.2.1.2

5.2.1.3

6.2.1.5

Level 2: The comparisons are generally correct, although may lack detail. The writing is mainly clear, although the structure may lack logic and comparisons are not always clear

3–4

Level 1: Some comparisons are correct. The writing lacks clarity, coherence and logic, and the comparisons are not clearly expressed.

1–2

No Relevant content

0

Indicative content

  • both have electrons
  • both have positive parts
  • plum pudding model has electrons all over the place whereas nuclear model has electrons in distinct shells
  • plum pudding is positive all over whereas nuclear model has a positive centre
  • nuclear model has a nucleus whereas plum pudding model does not
  • nuclear model shows electrons within different energy levels
  • nuclear model has neutrons whereas plum pudding does not

03.1

they conduct electricity in the solid and liquid states

1

03.2

giant metallic structure

ions arranged in regular patterns

electrons in outer shells/outermost electrons delocalised

1

1

1

03.3

atoms or ions are arranged in layers

that can slide over each other

1

1

03.4

most metals have high melting points/are solid at room temperature

1

AO3

04.1

giant/large

electrostatic

all

1

1

1

AO1

5.2.1.3

04.2

strong electrostatic forces of attraction between

ions/strong ionic bonds

require lots of energy to break bonds

1

1

AO1

5.2.2.3

04.3

lithium should have one ring with two dots/crosses, and sit within square brackets showing a positive charge

chlorine should have 3 rings, with two crosses/dots on the innermost ring, eight on the next, and seven on the outer most

a dot/cross representing the ion from lithium should be present on this outer ring

the ion should be in square brackets showing a negative charge

one mark for lithium

one mark for chloride

accept lithium with no electrons in the outer shell

2

AO2

5.2.1.3

04.4

lithium: bulb lit up

solid lithium chloride: bulb stays out

1

1

AO3

5.2.2.3

5.2.2.8

04.5

bulb lit up

because ions are free to move and carry charge

1

1

AO2

AO3

5.2.2.3

05.1

magnesium

1

AO1

5.2.1.5

05.2

good conductor – delocalised electrons

soft – arranged in layers

high melting point – lots of energy

1

1

1

AO1

5.2.27

5.2.2.8

05.3

alloy

1

AO1

5.2.2.7

05.4

harder

distort/disrupt

accept words to that effect for both marks

1

1

AO1

5.2.2.7

06.1

350

allow between 352 – 358

1

AO2

06.2

A

1

AO2 – 1

06.3

Level 3: The comparisons are detailed and accurate. The writing is clear, coherent and logical and comparisons are clearly made.

5-6

AO2

Level 2: The comparisons are generally correct, although may lack detail. The writing is mainly clear, although the structure may lack logic and comparisons are not always clear

3-4

Level 1: Some identifications are correct. The writing lacks clarity, coherence and logic, and the comparisons are not clearly expressed.

1-2

No relevant content.

0

Indicative content

  • B is mercury
    • lots of energy required to overcome the metallic bonding
    • so high boiling point
  • A is ethanol
  • C is hexanol
    • both are covalent molecules
    • only weak intermolecular forces need to be overcome
    • so less energy needed than mercury
    • hexanol is a larger molecule than ethanol, so had greater intermolecular forces (more energy required to overcome)

07.1

fluorine – covalent

lithium – metallic

lithium fluoride – ionic

one mark for one correct

one mark for all correct

2

AO1

5.2.1.3

5.2.1.4

5.2.1.5

07.2

positive ions

arranged in layers

attraction between positive metal ions and delocalised electrons

1

1

1

AO1

5.2.1.5

07.3

lithium should have one ring with two dots/crosses, and sit within square brackets showing a positive charge

fluorine should have 3 rings, with two crosses/dots on the innermost ring, and seven on the outer most

a dot/cross representing the ion from lithium should be present on this outer ring

the ion should be in square brackets showing a negative charge

accept lithium with no electrons in outer shell

1

AO2

5.2.1.5

07.4

does

free to move

1

1

AO1

5.2.2.3

08.1

MgCl2

the ‘2’ should be subscript

1

AO3

5.2.1.3

08.2

95

allow error carried forward from question 06.1

1

AO2

08.3

covalent

1

AO1

5.2.1..1

08.4

both have atoms arranged in layers

thus, both are soft

both have delocalised electrons

thus, both can conduct electricity

both have strong bonds holding atoms together

thus, both have high melting and boiling points

1

1

1

1

1

1

08.5

Level 3: Answer is detailed and accurate. The writing is clear, coherent and logical and comparisons are clearly made.

5-6

AO1

AO2

5.2.2.7

Level 2: Answer generally correct, although may lack detail. The writing is mainly clear, although the structure may lack logic and comparisons are not always clear

3-4

Level 1: Some correct points. The writing lacks clarity, coherence and logic, and the comparisons are not clearly expressed.

1-2

No relevant comment.

0

Indicative content:

  • pure metals have layers
  • layers can slide
  • thus, pure metals are soft
  • soft metals are not very useful for products
  • alloys are mixtures of metal with other elements
  • thus, alloys have distorted layers
  • thus, no layer can slide
  • making alloys harder
  • meaning they can be more useful

09.1

calcium: 2+

sulfur: 2–

1

1

AO2

5.2.1.2

09.2

calcium should have the following electron arrangement: 2,8,8,2 (shown as dots/crosses)

sulfur should have the following: 2,8,6 (shown as crosses/dots)

calcium sulphide should have:

calcium have the electron arrangement 2,8,8 with a 2+ positive charge

sulfur should have the electron arrangement 2,8,6 (shown as crosses/dots) with 2 additional electrons (shown as dots/crosses) taken from calcium and a

2– negative charge

1 mark for calcium

1 mark for sulfur

1 mark for calcium sulfide

1

1

1

AO2

5.2.1.2

09.3

advantage:

  • shows simplest ratio of atoms involved
  • shows 3D structure

disadvantage:

  • shows bonds acting in one direction (when they act in all directions)
  • only shows a small fraction of ions involved in ionic structure
  • not representative – atoms not calls and balls not sticks

accept any other suitable answers

1

1

AO3

5.2.1.3

10.1

A: gas

D: liquid

1

1

AO2

10.2

high melting point

conducts electricity when solid and liquid

1

1

AO2

10.3

C

sodium chloride is an ionic compound

high melting point

conducts electricity when liquid but not when solid

1

1

1

1

AO2

AO3

10.4

A

1

AO2

10.5

covalent bonds

small molecule

gas at room temperature

1

1

AO2

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