Transition Elements (OCR A Level Chemistry)

Exam Questions

3 hours34 questions
11 mark

Ethylenediamine, NH2CH2CH2NH2, is a bidentate ligand. It forms coordinate bonds with the metal ion from...

  • Both carbons

  • Both nitrogens

  • One carbon and one nitrogen

  • Any combination of carbon and nitrogen atoms

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21 mark

Which transition metal element has atoms with a sub-shell of 4s1?

  • Zinc

  • Iron

  • Copper

  • Vanadium

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31 mark

Two complex ions, [Cr(OH)6]3- and [Cr(NH3)6]3+ both contain chromium but form different colours in solution.

Which factor is the reason for this difference? 

  • Different ligands

  • Different overall charges

  • Different oxidation states of chromium

  • Different coordination numbers

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41 mark

Which is not true for scandium?

  • It cannot form coloured solutions and compounds

  • It does not make a good catalyst in solution

  • It only forms ions with the electronic configuration of [Ar]4s03d0

  • The stable ion is Sc2+

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51 mark

Which statement is true of the following reaction?

2Fe3+ (aq) + 2I- (aq) rightwards arrow2Fe2+ (aq) + I2 (aq)

  • Iron(III) ions are oxidised, iron(III) ions are the oxidising agent

  • Iron(III) ions are oxidised, iron(III) ions are the reducing agent

  • Iron(III) ions are reduced, iron(III) ions are the reducing agent

  • Iron(III) ions are reduced, iron(III) ions are the oxidising agent

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11 mark

What is the bonding between the ligands and the metal ion in [Fe(H2O)6]2+?

  • Metallic

  • Ionic

  • Hydrogen

  • Dative covalent

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21 mark

Which product is formed when aqueous Cr3+ ions are reacted with an excess of aqueous sodium hydroxide?

  • Cr(OH)63–

  • Cr(OH)3

  • [Cr(OH)4(H2O)2]

  • [Cr(OH)4]-

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31 mark

Which electron configuration(s) is / are correct?

  1. Cr atom: 1s22s22p63s23p63d54s1
  2. Cu atom: 1s22s22p63s23p63d104s1
  3. Fe2+ ion: 1s22s22p63s23p63d54s1
  • 1, 2 and 3

  • Only 1 and 2

  • Only 2 and 3

  • Only 1

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41 mark

Copper(II) ions form an aqueous complex ion, X, with chloride ions.

Which statement about X is true?

  • X has optical isomers

  • X has a square planar shape

  • X has the formula CuCl42+

  • X has a yellow colour

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51 mark

Which statement(s) is / are correct for the complex Pt(NH3)2Cl2?

  1. One of its stereoisomers is used as an anti-cancer drug.
  2. It has bond angles of 109.5°.
  3. It has optical isomers.
  • 1, 2 and 3

  • Only 1 and 2

  • Only 2 and 3

  • Only 1

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61 mark

The colour change for a reaction involving a chromium compound is shown below.

Chromium(III) sulfate rightwards arrow with Zn space divided by space straight H subscript 2 SO subscript 4 on top Blue solution

What is the change in oxidation state of chromium during this reaction?

  • +1

  • -1

  • +3

  • -3

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71 mark

Which of the following ions produces identical observations when sodium hydroxide or ammonia solutions are added until in excess?

  • [Fe(H2O)6]2+  

  • [Cr(H2O)6]3+   

  • [Cu(H2O)6]2+   

  • [Co(H2O)6]2+

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81 mark

Aqueous iron(III) ions react with sodium carbonate solution. 

What happens in the reaction?

 

Observation(s)

Product(s)

A

Brown precipitate and effervescence

Fe(H2O)3(OH)3 + CO2

B

Brown precipitate

Fe2(CO3)3

C

Orange solution

[Fe(H2O)5(OH)]2+

D

Brown precipitate and effervescence

Fe2(CO3)3 + CO2

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    91 mark

    Which statement(s) for the complex ion [Cu(NH2CH2CH2NH2)3]2+ is/are correct?

    1. It has cis and trans isomers.
    2. It has optical isomers.
    3. It is six-fold coordination.
    • 1, 2 and 3

    • Only 1 and 2

    • Only 2 and 3

    • Only 1

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    11 mark

    What colour change would you observe in the following reaction?

    [Cu(H2O)6]2+ (aq) + 4NH3 (aq) rightwards arrow[Cu(NH3)4(H2O)2]2+ (aq) + 4H2O (aq)

    • Blue solution, to a light blue precipitate, to a deep blue solution

    • Blue solution, to a deep blue solution

    • Blue solution, to a light blue precipitate

    • Deep blue solution, to a light blue precipitate, to a blue solution

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    21 mark

    Which electronic configuration corresponds to a transition metal that forms a pink solution?

    • [Ar]4s23d2

    • [Ar]4s03d4

    • [Ar]4s23d3

    • [Ar]4s03d5

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    31 mark

    How many electrons are gained by the dichromate ion, Cr2O72-, when it is reduced to the chromium(III) ion, Cr3+ ?

    • 4

    • 5

    • 6

    • 7

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    41 mark

    A substance undergoes the following separate tests to establish its identity:

    • sodium hydroxide is added: a green precipitate forms that does not redissolve in excess sodium hydroxide
    • ammonia is added: a green precipitate forms that does not redissolve in excess ammonia
    • silver nitrate is added: no change is observed
    • barium nitrate is added: a white precipitate is formed

    Identify the substance.

    • FeCl2

    • FeSO4

    • Cr2(SO4)3

    • CrCl3

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    51 mark

    The charges have been omitted from the complex ions shown.

    Identify which one is soluble.

    • [Cu(H2O)2(NH3)4]

    • [Fe(H2O)3(OH)3]

    • [Cu(H2O)4(OH)2]

    • [Co(H2O)3(OH)3]

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