A LevelChemistryOCRExam Questions5. Physical Chemistry & Transition ElementsTransition Elements

Transition Elements (OCR A Level Chemistry A): Exam Questions

Exam code: H432

3 hours38 questions

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Transition Elements

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1
1 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

Choose your answer

2
1 mark

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

  • Zinc

  • Iron

  • Copper

  • Vanadium

Choose your answer

3
1 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

Choose your answer

4
1 mark

Which statement 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+

Choose your answer

5
1 mark

The reaction of iron(III) ions with iodide ions is shown.

2Fe3+ (aq) + 2I- (aq) → 2Fe2+ (aq) + I2 (aq)

Which statement is correct?

  • 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

Choose your answer

1
1 mark

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

  • Metallic

  • Ionic

  • Hydrogen

  • Dative covalent

Choose your answer

2
1 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]-

Choose your answer

3
1 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

Choose your answer

4
1 mark

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

Which statement about X is correct?

  • X has optical isomers

  • X is square planar

  • X has the formula CuCl42+

  • X has a yellow colour

Choose your answer

5
1 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

Choose your answer

6
1 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

Choose your answer

7
1 mark

Which hexaaqua ion produces identical observations when sodium hydroxide or ammonia solution is added until in excess?

  • [Fe(H2O)6]2+  

  • [Cr(H2O)6]3+   

  • [Cu(H2O)6]2+   

  • [Co(H2O)6]2+

Choose your answer

8
1 mark

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

Which row is correct?

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

    Choose your answer

    9
    1 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

    Choose your answer

    10
    1 mark

    Which option shows the correct electron configuration for a copper(I) ion, Cu+?

    • 1s2 2s2 2p6 3s2 3p6 3d10 4s1

    • 1s2 2s2 2p6 3s2 3p6 3d10

    • 1s2 2s2 2p6 3s2 3p6 3d8 4s2

    • 1s2 2s2 2p6 3s2 3p6 3d9

    Choose your answer

    11
    1 mark

    Excess 1,2-diaminoethane (en) is added to an aqueous solution containing [Cr(H2O)6]3+ ions. A ligand substitution reaction occurs to form a new complex ion. 1,2-diaminoethane is a neutral, bidentate ligand.

    What are the coordination number and the oxidation state of the chromium in the new complex ion?

    Coordination number

    Oxidation state of chromium

    A

    3

    0

    B

    3

    +3

    C

    6

    0

    D

    6

    +3

      Choose your answer

      1
      1 mark

      What colour change would you observe in the following reaction?

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

      Choose your answer

      2
      1 mark

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

      • [Ar]4s23d2

      • [Ar]4s03d4

      • [Ar]4s23d3

      • [Ar]4s03d5

      Choose your answer

      3
      1 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

      Choose your answer

      4
      1 mark

      A substance undergoes the following separate tests.

      Test

      Observation(s)

      Sodium hydroxide

      Green precipitate forms that does not redissolve in excess sodium hydroxide

      Ammonia

      Green precipitate forms that does not redissolve in excess ammonia

      Silver nitrate

      No reaction

      Barium nitrate

      White precipitate forms

      Identify the substance.

      • FeCl2

      • FeSO4

      • Cr2(SO4)3

      • CrCl3

      Choose your answer

      5
      1 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]

      Choose your answer