Chemistry • Year 11 • Module 3 • Lesson 7
Metal Activity Series & Reactions of Metals
Lock in the NESA activity series order, the key reaction types, and the vocabulary needed to predict whether a displacement reaction will occur.
1. Term–definition match
Match each term to its definition. Write the correct term from the word bank in the right-hand column. 10 marks
Word bank: activity series • single displacement reaction • passivation • sacrificial protection • galvanising • ionisation energy • electronegativity • thermite reaction • spectator ion • cathodic protection
| # | Definition | Matching term |
|---|---|---|
| 1.1 | A ranking of metals from most to least reactive based on their tendency to lose electrons. | |
| 1.2 | A reaction in which a more reactive metal displaces a less reactive metal ion from its salt solution. | |
| 1.3 | Formation of a protective oxide layer on a metal surface that slows further corrosion (e.g. Al2O3 on aluminium). | |
| 1.4 | The energy required to remove an electron from a gaseous atom; lower values mean easier electron loss. | |
| 1.5 | A measure of an atom's tendency to attract electrons; metals lower in the activity series have higher values. | |
| 1.6 | An ion that does not change during a displacement reaction — the anion (e.g. SO42−) that stays in solution. | |
| 1.7 | The process of coating steel with zinc so the zinc corrodes preferentially, protecting the iron beneath. | |
| 1.8 | Connecting a more reactive metal (e.g. zinc) to a structure so it corrodes preferentially, protecting the structure. | |
| 1.9 | Another term for sacrificial protection emphasising the protected metal acts as a cathode. | |
| 1.10 | A highly exothermic single displacement: Al + Fe2O3 → Al2O3 + Fe; used in rail welding. |
2. True or false — with correction
Circle T or F for each statement. If false, write the corrected version on the line below. 10 marks (1 T/F + 1 correction where needed)
2.1 Copper reacts with dilute hydrochloric acid to produce copper chloride and hydrogen gas. T / F
2.2 Aluminium is less reactive than zinc because it does not react readily with dilute acids under normal conditions. T / F
2.3 In the NESA activity series, hydrogen is placed between lead and copper as a reference point. T / F
2.4 A metal with a larger atomic radius loses its valence electron more easily, making it more reactive. T / F
2.5 Zinc bolts are used on the Sydney Harbour Bridge because copper is too expensive, not for any chemical reason. T / F
3. Fill the gaps — predicting displacement reactions
Complete the paragraph below using the words in the box. Each word is used once. 8 marks
The is a ranking of metals from most to least , determined by their tendency to lose an . When a metal is added to a salt solution, a reaction only occurs if the added metal is in the series than the metal that is already in solution. In this case, the metal in solution is and forms a solid on the surface of the added metal. The anion (such as sulfate) acts as a ion — it does not change during the reaction. Metals that are in the activity series than hydrogen do not react with dilute acids.
4. Complete the reactions table
For each metal, tick the correct reaction behaviour and write the word equation where a reaction occurs. Use the NESA activity series: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au. 12 marks
| Metal | Reacts with cold water? | Reacts with dilute HCl? | Word equation (if reaction occurs — choose one reagent) |
|---|---|---|---|
| Sodium (Na) | Yes / No | Explosive — not used | |
| Magnesium (Mg) | Yes / No | Yes / No | |
| Zinc (Zn) | Yes / No | Yes / No | |
| Copper (Cu) | Yes / No | Yes / No | |
| Gold (Au) | Yes / No | Yes / No | |
| Iron (Fe) | Yes / No | Yes / No |
5. Function recall — why zinc protects iron
Answer each question in 1–2 sentences using precise lesson terms. 6 marks (2 each)
5.1 What is the function of zinc bolts in the Sydney Harbour Bridge at the chemical level? (Use the terms “activity series” and “electron loss”.)
5.2 What is the function of passivation in aluminium? (Why is passivation a misleading guide to aluminium's true position in the activity series?)
5.3 What is the function of hydrogen's position in the NESA activity series? (Why is a non-metal included?)
6. Build a concept map
Draw labelled arrows between the six terms below to show how they connect. Each arrow must carry a linking phrase (e.g. “determines”, “predicts”, “enables”). Aim for at least 6 labelled arrows. 6 marks
Supplied terms: atomic radius • ionisation energy • activity series • electron loss • displacement reaction • sacrificial protection
Q1 — Term–definition matches
1.1 activity series • 1.2 single displacement reaction • 1.3 passivation • 1.4 ionisation energy • 1.5 electronegativity • 1.6 spectator ion • 1.7 galvanising • 1.8 sacrificial protection • 1.9 cathodic protection • 1.10 thermite reaction
Q2 — True / False with corrections
2.1 False. Copper is below hydrogen in the activity series and does not react with dilute hydrochloric acid. No hydrogen gas is produced.
2.2 False. Aluminium is actually above zinc (more reactive) in the activity series. Its apparent lack of reactivity with dilute acids under normal conditions is due to passivation — the Al2O3 layer prevents contact with the reagent — not because Al has low reactivity.
2.3 True.
2.4 True.
2.5 False. Zinc is used because it is higher than iron in the activity series (more reactive), so it corrodes preferentially and protects the steel from corrosion by sacrificial protection. This is a deliberate electrochemical choice, not merely economic.
Q3 — Cloze paragraph
In order: activity series / reactive / electron / higher / ion / displaced / spectator / lower
Q4 — Reactions table (accept close paraphrases)
Na: Cold water — Yes (explosive). Word equation: sodium + water → sodium hydroxide + hydrogen.
Mg: Cold water — No (very slow / reacts with steam only). HCl — Yes. Word equation: magnesium + hydrochloric acid → magnesium chloride + hydrogen.
Zn: Cold water — No. HCl — Yes. Word equation: zinc + hydrochloric acid → zinc chloride + hydrogen.
Cu: Cold water — No. HCl — No. (Cu is below H in series.)
Au: Cold water — No. HCl — No. (Au is below H in series — least reactive.)
Fe: Cold water — No. HCl — Yes. Word equation: iron + hydrochloric acid → iron(II) chloride + hydrogen.
Q5.1 — Function of zinc bolts
Zinc is higher than iron in the activity series, meaning zinc has a greater tendency to lose electrons (be oxidised). When zinc bolts are in electrical contact with the steel panels and an electrolyte (moisture) is present, zinc loses electrons preferentially, acting as the anode. Iron acts as the cathode and is protected from corrosion — the zinc “sacrifices” itself.
Q5.2 — Function of passivation in aluminium
Passivation is the formation of a thin, impermeable Al2O3 layer on aluminium's surface that prevents further reaction with water or acid. This makes aluminium appear less reactive than it truly is; aluminium is actually above zinc in the activity series (more reactive) but passivation masks this high reactivity under normal laboratory conditions.
Q5.3 — Function of hydrogen in the activity series
Hydrogen is included as a reference point (not because it is a metal) to allow prediction of whether a metal will displace H+ ions from an acid. Any metal above hydrogen in the series will reduce H+ to H2 gas; any metal below (Cu, Ag, Au) cannot do this and does not dissolve in dilute HCl or H2SO4.
Q6 — Sample concept map
A correct map should include links such as:
- atomic radius (larger) → reduces nuclear attraction on outermost electron, lowering → ionisation energy
- ionisation energy (lower) → makes easier → electron loss
- electron loss → determines rank on the → activity series
- activity series → predicts whether → displacement reaction occurs
- activity series → enables design of → sacrificial protection
- electron loss → drives → sacrificial protection (more reactive metal loses electrons preferentially)
Award 1 mark per valid labelled arrow respecting causal direction (max 6).