Cambridge CIE IGCSE Chemistry Reactivity Series PDF

Head to www.savemyexams.com for more awesome resources Cambridge (CIE) IGCSE Your notes Chemistry Reactivity Series & Corrosion of Metals Contents Reactivity Series Explaining Reactivity Rusting of Iron Galva...

Head to www.savemyexams.com for more awesome resources Cambridge (CIE) IGCSE Your notes Chemistry Reactivity Series & Corrosion of Metals Contents Reactivity Series Explaining Reactivity Rusting of Iron Galvanising & Sacrificial Protection Page 1 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Reactivity Series Your notes Reactivity series What is the reactivity series of metals? The chemistry of the metals is studied by analysing their reactions with water and acids Based on these reactions a reactivity series of metals can be produced The series can be used to place a group of metals in order of reactivity based on the observations of their reactions with water and acids The non-metals hydrogen and carbon are also included in the reactivity series as they are used to extract metals from their oxides Reactivity Series of Metals Metal Reaction with cold water Reaction with acid Reaction with oxygen Most reactive Potassium Reacts violently Reacts violently Reacts quickly in air Sodium Reacts quickly Reacts quickly Reacts quickly in air Calcium Reacts less strongly Reacts vigorously Reacts readily Magnesium Slow reaction (reacts with steam) Reacts vigorously Reacts readily Aluminium Slow reaction (reacts with steam) Reacts readily Reacts readily Carbon Zinc Very slow reaction (reacts slowly with Reacts less Reacts steam) strongly Iron Very slow reaction (reacts slowly with Reacts less Reacts steam) strongly Page 2 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Hydrogen Your notes Copper No reaction with steam or water No reaction Reacts Silver No reaction with steam or water No reaction Reacts Gold No reaction with steam or water No reaction No reaction Least reactive How to remember the reactivity series Observations from the table above allow the following reactivity series to be deduced The order of this reactivity series can be memorised using the following mnemonic “Please send cats, monkeys and cute zebras into hot countries signed Gordon" Reactivity Series Mnemonic Metal Abbreviation Most reactive Potassium P - Please Sodium S - send Calcium C - cats, Magnesium M - monkeys, Aluminium A - and Carbon C - cute Zinc Z - zebras Page 3 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Iron I - into Your notes Hydrogen H - hot Copper C - countries Silver S - signed Gold G - Gordan Least reactive Reaction of metals with cold water The more reactive metals will react with cold water to form a metal hydroxide and hydrogen gas Potassium, sodium and calcium all undergo reactions with cold water as they are the most reactive metals: metal + water → metal hydroxide + hydrogen For example, calcium and potassium: Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g) 2K (s) + 2H2O (l) → 2KOH (aq) + H2 (g) Reactions of metals with steam Metals just below calcium in the reactivity series do not react with cold water but will react with steam to form a metal oxide and hydrogen gas, for example, magnesium: Mg (s) + H2O (g) → MgO (s) + H2 (g) Reaction with dilute acids Only metals above hydrogen in the reactivity series will react with dilute acids Unreactive metals below hydrogen, such as gold, silver and copper, do not react with acids The more reactive the metal then the more vigorous the reaction will be Metals that are placed high on the reactivity series such as potassium and sodium are very dangerous and react explosively with acids Page 4 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources When acids react with metals they form a salt and hydrogen gas: The general equation is: Your notes metal + acid ⟶ salt + hydrogen Some examples of metal-acid reactions and their equations are given below: Acid-Metal Reactions Table Metal Sulfuric acid Hydrochloric acid Magnesium Mg + H2SO4 → MgSO4 + H2 Mg + 2HCl → MgCl2 + H2 Zinc Zn + H2SO4 → ZnSO4 + H2 Zn + 2HCl → ZnCl2 + H2 Iron Fe + H2SO4 → FeSO4 + H2 Fe + 2HCl → FeCl2 + H2 Reaction with oxygen Some reactive metals, such as the alkali metals, react easily with oxygen Silver, copper and iron can also react with oxygen although much more slowly When metals react with oxygen a metal oxide is formed, for example, copper: metal + oxygen → metal oxide 2Cu (s) + O2 (g) → 2CuO (s) Gold does not react with oxygen Deducing the order of reactivity The order of reactivity of metals can be deduced by making experimental observations of reactions between metals and water, acids and oxygen The more vigorous the reaction of the metal, the higher up the reactivity series the metal is A combination of reactions may be needed, for example, the order of reactivity of the more reactive metals can be determined by their reactions with water The less reactive metals react slowly or not at all with water, so the order of reactivity would need to be determined by observing their reactions with dilute acid Temperature change in a reaction can also be used to determine the order of reactivity The greater the temperature change in a reaction involving a metal, the more reactive the metal is Page 5 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Explaining Reactivity Your notes Explaining reactivity Extended tier only Metal atoms form positive ions by loss of electrons when they react with other substances The tendency of a metal to lose electrons is a measure of how reactive the metal is A metal that is high up on the series loses electrons easily and is thus more reactive than one which is lower down on the series Displacement reactions between metals and aqueous solutions of metal salts Any metal will displace another metal that is below it in the reactivity series from a solution of one of its salts This is because more reactive metals lose electrons and form ions more readily than less reactive metals, making them better reducing agents The less reactive metal is a better electron acceptor than the more reactive metal, thus the less reactive metal is reduced OILRIG: reduction is gain of electrons Magnesium + copper sulfate Magnesium is a reactive metal and can displace copper from a copper sulfate solution Magnesium loses its electrons more easily and the ion of the less reactive metal, copper, will gain these electrons to form elemental copper This is easily seen as the more reactive metal slowly disappears from the solution, displacing the less reactive metal magnesium + copper sulfate → magnesium sulfate + copper Mg (s) + CuSO4 (aq) → MgSO4 (aq) + Cu (s) The blue colour of the CuSO4 solution fades as colourless magnesium sulfate solution is formed Copper coats the surface of the magnesium and also forms solid metal which falls to the bottom of the beaker The reaction between magnesium and copper sulfate Page 6 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Your notes Diagram showing the colour change when magnesium displaces copper from copper sulfate By combining different metals and metal salts solutions it is possible to come up with a relative reactivity order Metal Solutions Displacement Table Mixture Products Equation for Reaction Magnesium and iron(II) sulfate Magnesium sulfate and iron Mg + FeSO4 → MgSO4 + Fe Zinc and iron chloride Zinc chloride and iron Zn + FeCl2 → ZnCl2 + Fe Iron and silver nitrate Iron(II) nitrate and silver Fe + AgNO3 → Fe(NO3)2 + 2Ag Copper and iron(II) chloride No reaction ------ Silver and copper(II) sulfate No reaction ------ Zinc and magnesium chloride No reaction ------ Page 7 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources From this table we can deduce the order of reactivity: Magnesium and zinc are both more reactive than iron but magnesium is more reactive than zinc Your notes Copper and silver are both less reactive than iron but silver is less reactive than copper The order of reactivity of the metals tested can be therefore be deduced as: Mg > Zn > Fe > Cu > Ag Reactivity of aluminium Aluminium is high in the reactivity series, but in reality, it does not react with water and the reaction with dilute acids can be quite slow This is because it reacts readily with oxygen, forming a protective layer of aluminium oxide which is very thin This layer prevents reaction with water and dilute acids, so aluminium can behave as if it is unreactive Page 8 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Rusting of Iron Your notes Rusting of iron What is rusting? Rust is a chemical reaction between iron, water and oxygen to form the compound hydrated iron(III) oxide (rust) Oxygen and water must be present for rust to occur During rusting, iron is oxidised iron + water + oxygen → hydrated iron(III) oxide Investigating rusting To investigate the conditions required for rusting, prepare three test tubes as shown in the diagram The oil in the 2nd tube keeps out air and the water has been boiled so that no air is left in it The calcium chloride in the 3rd tube is used to remove any moisture in the air After a few days, the iron nail in the 1st tube will be the only nail to show signs of rust Requirements for rusting Page 9 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Diagram showing the requirements of oxygen and water for rust to occur: only the nail on the left rusts Rust prevention methods Your notes Rust can be prevented by coating iron with barriers that prevent the iron from coming into contact with water and oxygen However, if the coatings are washed away or scratched, the iron is once again exposed to water and oxygen and will rust Table to show common barrier methods Common barrier methods Grease Oil Paint Plastic Examiner Tips and Tricks Only iron or steel (an alloy made from iron) can rust. If any other metal oxidises in air causing the metal to break down, you should say that the metal has corroded. Page 10 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Galvanising & Sacrificial Protection Your notes Galvanising & sacrificial protection Extended tier only Sacrificial Protection Iron can be prevented from rusting using the reactivity series A more reactive metal can be attached to a less reactive metal The more reactive metal will oxidise and therefore corrode first, protecting the less reactive metal from corrosion Zinc bars on the side of steel ships Diagram to show the use of zinc bars on the sides of steel ships as a method of sacrificial protection Zinc is more reactive than iron therefore will lose its electrons more easily than iron and is oxidised more easily: Zn → Zn2+ + 2e- The iron is less reactive therefore will not lose its electrons as easily so it is not oxidised; the zinc is sacrificed to protect the steel For continued protection, the zinc bars have to be replaced before they completely corrode Page 11 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers  Head to www.savemyexams.com for more awesome resources Galvanising Galvanising is a process where the iron to be protected is coated with a layer of zinc Your notes This can be done by electroplating or dipping it into molten zinc ZnCO3 is formed when zinc reacts with oxygen and carbon dioxide in the air and protects the iron by the barrier method If the coating is damaged or scratched, the iron is still protected from rusting by sacrificial protection Examiner Tips and Tricks You maybe asked to explain why a metal is/is not suitable as a method of preventing an iron/steel object from rusting. Remember that if it is higher in the reactivity series than iron, it will be suitable for sacrificial protection as it will be oxidised instead of iron. If it is lower in the reactivity series than iron, it would not be suitable as iron would be oxidised, causing it to rust. Page 12 of 12 © 2015-2025 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers