A Level Chemistry (A2) chapter 6: Chemistry of transition elements MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

124 exam-style questions on Chemistry of transition elements, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

124 questions · 5 topics · 10 per test

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What chapter 6 covers

Ten Chemistry of transition elements questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. Kstab for [Cu(NH3)4(H2O)2]2+ is 1.2 × 1013 dm12 mol−4. What equilibrium concentration of free NH3, in mol dm−3, makes the concentration of the ammine complex 99 times the concentration of [Cu(H2O)6]2+?

  1. A
    8.3 × 10−12
  2. B
    2.9 × 10−6
  3. C
    5.4 × 10−4
  4. D
    1.7 × 10−3
Show answer

Answer: D. 99 = Kstab × [NH3]4, so [NH3]4 = 99 / 1.2 × 1013 = 8.3 × 10−12 and [NH3] = 1.7 × 10−3 mol dm−3. Forgetting the fourth root leaves 8.3 × 10−12; taking a square root gives 2.9 × 10−6.

2. The complex [Ni(H2NCH2CH2NH2)3]2+ exists as two optical isomers. Which statement about their polarity is correct?

  1. A
    both isomers are polar, with dipoles pointing in opposite directions
  2. B
    one isomer is polar and the other is non-polar
  3. C
    neither isomer is polar, because the three identical ligands are arranged symmetrically so the bond dipoles cancel
  4. D
    both isomers are polar, because every chiral species must be polar
Show answer

Answer: C. The three identical bidentate ligands are spread evenly around the nickel ion, so the dipoles cancel in each isomer even though the complex is chiral. Chirality and polarity are separate properties: a mirror image always has the same polarity as the original.

3. Zinc is a d-block element but is not a transition element. Why?

  1. A
    its only ion, Zn2+, has a full 3d sub-shell
  2. B
    it has no electrons in its 3d sub-shell
  3. C
    its Zn2+ ion has an incomplete 3d sub-shell
  4. D
    it does not form any complex ions
Show answer

Answer: A. A transition element forms at least one stable ion with an incomplete d sub-shell. Zinc forms only Zn2+, [Ar] 3d10, with a full 3d sub-shell. Zinc does form complex ions, such as [Zn(NH3)4]2+.

4. Which ion has an incomplete 3d subshell?

  1. A
    Fe3+
  2. B
    Zn2+
  3. C
    Cu+
  4. D
    Sc3+
Show answer

Answer: A. Fe3+ is [Ar]3d5, a partly filled 3d subshell. Zn2+ and Cu+ are 3d10 (full) and Sc3+ is 3d0 (empty).

5. Which property is expected to differ between cis-[Pt(NH3)2Cl2] and trans-[Pt(NH3)2Cl2]?

  1. A
    relative molecular mass
  2. B
    coordination number of platinum
  3. C
    solubility in water
  4. D
    oxidation state of platinum
Show answer

Answer: C. The cis isomer is polar and the trans isomer is not, so the cis form dissolves better in polar water. Both have the same formula, so the same Mr, coordination number (4) and oxidation state (+2).

6. Kstab for [Ag(NH3)2]+ is 1.7 × 107 dm6 mol−2. In a solution at equilibrium, the concentration of [Ag(NH3)2]+ is 0.050 mol dm−3 and [NH3] = 0.20 mol dm−3. What is [Ag+]?

  1. A
    1.5 × 10−8 mol dm−3
  2. B
    7.4 × 10−8 mol dm−3
  3. C
    1.4 × 107 mol dm−3
  4. D
    3.4 × 104 mol dm−3
Show answer

Answer: B. [Ag+] = [complex]/(Kstab × [NH3]2) = 0.050/(1.7 × 107 × 0.040) = 7.4 × 10−8 mol dm−3. Forgetting to square [NH3] gives 1.5 × 10−8. Almost all the silver is in the complex.

7. Cu2+ is a 3d9 ion. In the octahedral complex [Cu(H2O)6]2+, how many d electrons are in the higher-energy set of orbitals?

  1. A
    1
  2. B
    2
  3. C
    3
  4. D
    4
Show answer

Answer: C. The three lower orbitals hold six electrons, leaving three for the two higher orbitals (one pair and one single electron). This vacancy in the upper set is what allows a d−d transition.

8. In an octahedral complex, chloride ions replace the water ligands without a change of shape, and ΔE between the split d orbitals becomes smaller. What happens to the light absorbed?

  1. A
    light of higher frequency (shorter wavelength) is absorbed, so the colour seen changes
  2. B
    light of lower frequency (longer wavelength) is absorbed, so the colour seen changes
  3. C
    light of the same frequency is absorbed, but more strongly
  4. D
    no visible light is absorbed any more, so the complex becomes colourless
Show answer

Answer: B. ΔE = hf, so a smaller ΔE means a lower frequency (longer wavelength) of light is absorbed. A different part of the spectrum is removed, so the complementary colour seen changes.

9. How are the five 3d orbitals of a transition metal ion split in an octahedral complex?

  1. A
    three orbitals at higher energy and two at lower energy
  2. B
    two orbitals at higher energy and three at lower energy
  3. C
    one orbital at higher energy and four at lower energy
  4. D
    they all remain at the same energy
Show answer

Answer: B. In an octahedral complex the ligands approach along the x, y and z axes. The two d orbitals that point along the axes are repelled more and rise in energy; the three that point between the axes form the lower set.

10. An iron tablet is dissolved in dilute sulfuric acid so that all the iron is present as Fe2+. The solution needs 12.50 cm3 of 0.0100 mol dm−3 KMnO4 to reach the end-point.
MnO4− + 8H+ + 5e− → Mn2+ + 4H2O
What mass of iron did the tablet contain? (Ar: Fe = 55.8)

  1. A
    6.98 mg
  2. B
    1.40 mg
  3. C
    34.9 mg
  4. D
    94.9 mg
Show answer

Answer: C. Each MnO4− gains five electrons and each Fe2+ gives one (Fe2+ → Fe3+ + e−), so the ratio is 1 : 5. Moles of MnO4− = 1.25 × 10−4, so moles of Fe2+ = 6.25 × 10−4 and the mass of iron is 6.25 × 10−4 × 55.8 = 0.0349 g = 34.9 mg. A 1 : 1 ratio gives 6.98 mg.

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Chemistry of transition elements: questions students ask

How many Chemistry of transition elements MCQs are there?

124, each with the answer and a short explanation, across 5 topics: General physical and chemical properties of the first row of transition elements, titanium to, General characteristic chemical properties of the first set of transition elements, titanium to, Colour of complexes, Stereoisomerism in transition element complexes, Stability constants, K. Every chapter test draws ten of them, so you can take it many times.

Is the A Level Chemistry (A2) chapter 6 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

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