Lesson 3.2.5.4

3.2.5.4 Formation of coloured ions Quiz: AQA Chemistry, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.2.5.4, Formation of coloured ions: 20 multiple choice questions for the AQA Chemistry (7405), Unit 2: Inorganic chemistry, written with Revision Ninja.

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The 20 questions

  1. Transition metal complexes appear coloured because they absorb specific wavelengths of what?

    • Visible light
    • Infrared radiation
    • Ultraviolet light
    • Microwave radiation

  2. When visible light is absorbed by a complex ion, d electrons move to what state?

    • Ionised state
    • Ground state
    • Gaseous state
    • Excited state

  3. Which equation gives the energy difference between the ground and excited d electron states?

    • delta E = nRT
    • delta E = kT
    • delta E = mc^2
    • delta E = h x nu = hc/lambda

  4. Which of these factors does NOT alter the d-orbital energy gap Delta E in a complex?

    • Solution concentration
    • Oxidation state
    • Co-ordination number
    • Ligand type

  5. What is the wavelength of light absorbed when delta E = 3.98 x 10^-19 J? (h = 6.63 x 10^-34 J s, c = 3.00 x 10^8 m s-1)

    • 600 nm
    • 700 nm
    • 500 nm
    • 400 nm

  6. A solution absorbs mainly red light. What colour does it appear?

    • Yellow
    • Red
    • Blue-green
    • Black

  7. Which transition metal ion forms a characteristic pale green aqueous solution?

    • Iron(III)
    • Chromium(III)
    • Iron(II)
    • Copper(II)

  8. What colour is observed when a complex ion absorbs light in the blue region?

    • Green
    • Yellow
    • Blue
    • Red

  9. Replacing water ligands with ammonia ligands changes a complex colour by altering what?

    • Ionisation energy
    • Enthalpy change
    • Activation energy
    • Energy gap Delta E

  10. Why do [Cu(H2O)6]2+ and [CuCl4]2- absorb different wavelengths of visible light?

    • Different pH values
    • Different Delta E
    • Different solution temperatures
    • Different copper isotopes

  11. A solution has an absorbance reading that is directly proportional to concentration. Which law is being obeyed?

    • Charles's law
    • Hess's law
    • Boyle's law
    • Beer-Lambert law

  12. Why is the aqueous zinc ion, Zn2+, colourless?

    • Empty d subshell
    • No d electrons
    • Incomplete d subshell
    • Full d subshell

  13. What is the energy gap delta E for absorption of light with wavelength 600 nm? (h = 6.63 x 10^-34 J s, c = 3.00 x 10^8 m s-1)

    • 9.9 x 10^-19 J
    • 3.3 x 10^-19 J
    • 6.6 x 10^-19 J
    • 1.1 x 10^-19 J

  14. Changing a complex ion's co-ordination number alters its colour by changing what?

    • Speed of light
    • Planck constant
    • Energy gap Delta E
    • Avogadro constant

  15. Which d-block metal ion is colourless in aqueous solution due to a full d sub-shell?

    • Manganese(II)
    • Scandium(III)
    • Titanium(III)
    • Vanadium(IV)

  16. Why does changing the ligand in a transition metal complex alter its colour?

    • Changes oxidation state
    • Alters d-orbital splitting
    • Alters nuclear charge
    • Changes atomic radius

  17. Which transition metal ion gives a blue colour in aqueous solution?

    • Na+
    • Zn2+
    • Ca2+
    • Cu2+

  18. Where do d electrons move when visible light is absorbed by a transition metal complex?

    • Ground state
    • Surrounding ligands
    • Inner shells
    • Excited state

  19. What process causes light absorption in transition metal complexes?

    • Thermal expansion
    • Nuclear excitation
    • d-electron promotion
    • Ligand dissociation

  20. What is the approximate wavelength in nm for light of energy 2.0 x 10^-19 J? (h = 6.63 x 10^-34 J s, c = 3.00 x 10^8 m s-1)

    • 1000 nm
    • 100 nm
    • 3000 nm
    • 500 nm

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