AQA GCSE Chemistry Foundation (8462), Foundation tier · Atomic structure and the periodic table › Properties of transition metals
Practise Typical properties. 7 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
Three typical properties of the transition metals: many form ions with different charges, they form coloured compounds, and they and their compounds are useful as catalysts. You need examples using Cr, Mn, Fe, Co, Ni and Cu. This is in GCSE Chemistry only, not in Combined Science.
Key facts
Typical properties: ions with different charges, coloured compounds, useful as catalysts
Iron: Fe2+ and Fe3+; copper: Cu+ and Cu2+
Roman numeral = charge on the metal ion: iron(III) = Fe3+
Copper(II) sulfate solution: blue; iron(II): pale green; iron(III): orange-brown
Many transition metals form ions with different charges: iron forms Fe2+ and Fe3+; copper forms Cu+ and Cu2+; chromium forms Cr2+ and Cr3+; cobalt forms Co2+ and Co3+.
One metal, two ions, two colours: typical of a transition metal.
Group 1 metals only ever form 1+ ions.
A Roman numeral in the name gives the charge on the metal ion: iron(II) chloride is FeCl2; iron(III) chloride is FeCl3; copper(II) oxide is CuO; copper(I) oxide is Cu2O.
Coloured compounds
Transition metal compounds are often coloured. Group 1 compounds are white and dissolve to give colourless solutions.
Examples: copper(II) sulfate solution is blue; iron(II) compounds are pale green; iron(III) compounds are orange-brown; nickel(II) compounds are green; potassium manganate(VII) is purple; potassium dichromate(VI) is orange.
Ions of the same metal with different charges can have different colours, e.g. iron(II) and iron(III).
The colours are used to colour glass and pottery glazes, and to identify metal ions in tests.
Catalysts
Transition metals and their compounds are useful as catalysts: they speed up reactions without being used up.
Iron is the catalyst in the Haber process for making ammonia.
Nickel is the catalyst for the reaction of hydrogen with alkenes.
Manganese(IV) oxide catalyses the decomposition of hydrogen peroxide into water and oxygen.
How to answer each type of question
Compare transition metal compounds with Group 1 compounds
2 to 3 marksGrade 4
Use the three typical properties: different ion charges, coloured compounds, catalysts.
Write each point as a comparison with the Group 1 metal.
Example. Cobalt is a transition metal. Sodium is in Group 1. Give two ways in which the compounds of cobalt are different from the compounds of sodium.
Show the model answerHide the model answer
Cobalt compounds are coloured, but sodium compounds are white (1). Cobalt forms ions with different charges (Co2+ and Co3+), but sodium only forms Na+ ions (1).
Don’t lose marks
Saying the metals themselves are coloured. It is their compounds that are typically coloured.
Saying a catalyst is used up in the reaction. It is not used up.
Reading the Roman numeral as the number of atoms: iron(III) oxide is Fe2O3, not FeO3.
Giving Group 1 behaviour, such as reacting vigorously with water, as a transition metal property.
More tips
Memory tricks
Transition metals are 'three Cs': Coloured compounds, different Charges, Catalysts.
Roman numeral = charge: (II) = 2+, (III) = 3+.
Catalyst pairs: iron → Haber process; nickel → hydrogen + alkenes; manganese(IV) oxide → hydrogen peroxide.
Exam technique
When asked for an example, name a compound or use involving Cr, Mn, Fe, Co, Ni or Cu.
When comparing with Group 1, write a matched pair for each property.
Use Roman numerals to work out formulae by balancing the charges.
What each grade needs
What you need to be able to do, from the first marks up to the top grade.
Grade 4
State three typical transition metal propertiesIons with different charges, coloured compounds, and use as catalysts.
Grade 5
Give examples of coloured compoundse.g. copper(II) sulfate solution is blue; iron(III) compounds are orange-brown.
Grade 5
Give examples of transition metal catalystsIron in the Haber process; nickel for adding hydrogen to alkenes; manganese(IV) oxide for decomposing hydrogen peroxide.
Quick recall
Cover the answers and test yourself. The app has these as flashcards that come back just before you'd forget them.
Chromium, manganese, iron, cobalt, nickel and copper are transition metals. What colour is copper(II) sulfate solution?
blue
Copper forms two oxides, Cu2O and CuO. The oxide ion is O2−. Give the charge on the copper ion in each oxide.
Cu2O: 1+; CuO: 2+
Give the typical colour of a solution of a copper(II) compound.
blue
Deduce the charge on the chromium ion in Cr2O3. Show your working.
3+
Which typical property of transition metal compounds is shown by cobalt chloride and copper(II) sulfate?
They are coloured.
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
Chromium, manganese, iron, cobalt, nickel and copper are transition metals.
(a) Which is a typical property of compounds of transition metals? Tick (✓) one box.[1]
They are always white.
They are often coloured.
They are all gases.
They only contain ions with a 1+ charge.
(b) What colour is copper(II) sulfate solution?[1]
(c) Iron is used as a catalyst in the Haber process to make ammonia. What does a catalyst do?[1]
(d) Iron forms Fe2+ ions and Fe3+ ions. The oxide ion is O2−. Give the formula of iron(III) oxide.[1]
Show the answer and mark scheme
(a)Answer: They are often coloured.
(b)Answer: blue
blue
(c)Answer: It speeds up a reaction without being used up.
speeds up / increases the rate of a (chemical) reaction
(d)Answer: Fe2O3
Fe2O3
Question 2Medium6 marks
Many transition metals form ions with different charges.
(a) Copper forms two oxides, Cu2O and CuO. The oxide ion is O2−. Give the charge on the copper ion in each oxide.[2]
(b) Give the formula of the compound formed between Fe3+ ions and Cl− ions.[1]
(c) Solutions that contain Fe2+ ions are pale green. Solutions that contain Fe3+ ions are yellow-brown. A student left some iron(II) sulfate solution open to the air for a week. The solution turned yellow-brown. Suggest what happened to the iron ions.[1]
(d) Many transition metals and their compounds are useful as catalysts. Name one transition metal, or compound of a transition metal, that is used as a catalyst. Name the process or reaction it catalyses.[2]
Show the answer and mark scheme
(a)Answer: Cu2O: 1+; CuO: 2+
Cu2O: 1+ / Cu+
CuO: 2+ / Cu2+
(b)Answer: FeCl3
FeCl3
(c)Answer: The Fe2+ ions changed into Fe3+ ions (they were oxidised by oxygen in the air).
Fe2+ ions changed into Fe3+ ions / iron(II) was oxidised to iron(III)
(d)Answer: e.g. iron, which is the catalyst in the Haber process for making ammonia.
a named transition metal or transition metal compound used as a catalyst, e.g. iron / manganese(IV) oxide / nickel
a correct process or reaction for the catalyst named, e.g. iron: the Haber process (making ammonia) / manganese(IV) oxide: decomposition of hydrogen peroxide / nickel: adding hydrogen to alkenes