Exam code: 5070
Aluminium is extracted by electrolysis. Iron is extracted from its ore by reduction with carbon.
Iron is a transition element. Give two ways in which the properties of transition elements differ from the properties of Group I metals.
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Describe three properties of iron that show that it is a transition element and not a Group I element.
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The table shows the melting point and the density of three metals.
metal | melting point / °C | density / g cm-3 |
|---|---|---|
sodium | 98 | 0.97 |
iron | 1538 | 7.87 |
copper | 1085 | 8.96 |
Which metal in the table is not a transition element?
Use the data in the table to describe two ways in which the transition elements in the table differ from sodium.
Copper(II) sulfate dissolves in water to give a blue solution. Sodium sulfate dissolves to give a colourless solution.
i) State what this shows about the compounds of the transition elements.
[1]
ii) A student writes that copper is blue. Explain why this is not correct.
[1]
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Hydrogen peroxide solution decomposes very slowly at room temperature. When a small amount of manganese(IV) oxide is added, the solution fizzes and the decomposition becomes much faster.
Name the property of the transition elements that manganese(IV) oxide is showing here.
At the end of the reaction the manganese(IV) oxide is filtered off, dried and weighed. Its mass is unchanged.
Explain how this result supports your answer to part (a).
Suggest why a compound of a transition element is used for this purpose rather than a compound of a Group I metal.
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Iron forms two different chlorides. Their formulae are FeCl2 and FeCl3.
Deduce the oxidation number of iron in each chloride.
Name the property of the transition elements shown by iron forming both of these chlorides.
Sodium forms only one chloride, NaCl.
Explain why sodium cannot form a second chloride in the way that iron does.
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The diagram shows part of the structures of sodium bromide and sulfur.
Describe both sodium bromide and sulfur in terms of:
bonding
electrical conductivity
solubility in water
Sulfur is an element.
What is meant by the term element?
A coloured crystal of cobalt(II) chloride is placed at the bottom of a beaker containing water. Colour spreads throughout the water over time. Figure 1 shows the spread of colour after two days.
Figure 1
Cobalt is a transition element. Lithium is a Group I element.
Describe two ways in which the properties of cobalt differ from those of lithium.
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Chromium is a transition element. Two of its oxides are Cr2O3 and CrO3.
Deduce the oxidation number of chromium in each oxide.
The properties of the transition elements can be sorted into physical properties and chemical properties.
i) Give one physical property of the transition elements.
[1]
ii) Give one chemical property of the transition elements.
[1]
iii) Explain why acting as a catalyst is a chemical property rather than a physical property.
[1]
Chromium(III) oxide is a green solid. Chromium metal is a shiny silver-grey solid.
Explain what this tells you about where the colour of a transition element compound comes from.
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A student is given four solids.
solid | appearance | effect on the decomposition of hydrogen peroxide |
|---|---|---|
W | white | no change in rate |
X | green | no change in rate |
Y | black | rate increases |
Z | white | rate increases |
i) Give the letter of one solid which gives evidence that a transition element is present because of its appearance.
[1]
ii) Give the letter of one solid which gives evidence that a transition element is present because of its effect on the hydrogen peroxide.
[1]
iii) Give the letter of the solid for which there is no evidence that a transition element is present.
[1]
Solid Z is white but it does increase the rate of the decomposition.
Explain why the student cannot conclude from the table alone whether solid Z contains a transition element.
Zinc lies in the same block of the Periodic Table as the transition elements. All zinc compounds are white and dissolve to give colourless solutions.
Suggest why this makes zinc an unusual member of that block.
Suggest one further test the student could carry out on a zinc compound to investigate whether it behaves like a transition element.
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A student is asked to describe two ways in which chromium differs from potassium. Chromium is a transition element and potassium is a Group I metal.
The student writes three statements.
1 | Chromium is hard. |
2 | Chromium forms coloured compounds and potassium does not. |
3 | Chromium conducts electricity and potassium does not. |
For each statement, explain whether it would be credited.
Rewrite statement 1 so that it would be credited.
In a later answer the same student writes that chromium is coloured.
Explain why this would not be credited.
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A solid compound R dissolves in water to give a colourless solution.
State what this suggests about compound R.
Give the reason for your answer.
Compound R is later found to be zinc sulfate. Zinc lies in the same block of the Periodic Table as the transition elements, and all zinc compounds are white and give colourless solutions.
Explain what this tells you about using colour on its own to decide whether an element belongs to that block.
Suggest a different property that could be investigated to help decide whether a metal belongs to that block of the Periodic Table.
State what result would support the conclusion.
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Scandium, proton number 21, is not a typical transition element.
Scandium is a low density metal which has only one oxidation state in its compounds. Scandium compounds are white solids which form colourless solutions. Titanium, the next metal in the period, is a far more typical transition element.
How would the properties of titanium differ from those of scandium?
Scandium fluoride is an ionic compound. The valency of scandium in scandium fluoride is three.
Draw a diagram which shows the formula of this compound, the charges on the ions and the arrangement of the valency electrons around the negative ions.
Use × to represent an electron from a fluorine atom.
Use ○ to represent an electron from a scandium atom.
Scandium oxide is insoluble in water. Describe how you could show that it is an amphoteric oxide.
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This question is concerned with the elements in Period 5, Rb to Xe.
The electron distributions of some of these elements are given in the following list.
Element B | 2 + 8 + 18 + 18 + 8 |
Element C | 2 + 8 + 18 + 18 + 5 |
Element D | 2 + 8 + 18 +18 + 6 |
Element E | 2 + 8 + 18 + 18 + 4 |
Element F | 2 + 8 + 18 + 18 + 7 |
i) Identify element C.
[1]
ii) Which element in the list does not form any compounds?
[1]
iii) Which element in the list forms a chloride of the type XCl2?
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iv) Which two elements would react together to form a compound of the type XY4?
[1]
Predict two differences in physical properties and two differences in chemical properties between rubidium and the transition metal niobium.
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A student claims that element G is a transition element.
Four pieces of information about G are available.
1 | The density of G is 1.74 g cm-3. |
2 | G melts at 650 °C. |
3 | G forms only one chloride, of formula GCl2. |
4 | The oxide of G is a white solid. |
Evaluate the student's claim, using all four pieces of information.
Deduce which group of the Periodic Table G is most likely to be in.
Give a reason for your answer.
Another student suggests that, because the oxide of G is white, this alone proves that G is not in the same block of the Periodic Table as the transition elements.
Explain why this suggestion is wrong.
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A compound of a metal is thought to act as a catalyst.
Describe how a student could obtain evidence for this, stating what would be measured and what results would support the conclusion.
A metal M forms two chlorides, MCl2 and MCl3.
Explain how these two formulae provide evidence that M is a transition element.
A third student says that finding a coloured compound of a metal is the quickest way to prove that the metal is a transition element.
Explain why this method is less reliable than the evidence in parts (a) and (b).
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In an industrial process, a compound of a transition element is packed into a reactor. Over many months the same compound continues to speed up the reaction, and only a small amount has to be replaced.
Explain why the compound does not have to be replaced after each batch.
The company tests a compound of a Group I metal in the same reactor under the same conditions. The rate of reaction is unchanged.
Suggest what this result shows.
The reactor operates at 450 °C.
Suggest one physical property of transition elements that makes a transition metal suitable for building the parts of the reactor.
Justify your answer.
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