Lesson 15A.1

15A.1 Electronic configurations and oxidation states Quiz: Pearson Edexcel Chemistry, Unit 15

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 15A.1, Electronic configurations and oxidation states: 20 multiple choice questions for the Pearson Edexcel Chemistry (9CH0), Unit 15: Transition Metals, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What is the electronic configuration of an iron atom?

    • [Ar] 3d6 4s2
    • [Ar] 3d4 4s2
    • [Ar] 3d8
    • [Ar] 3d7

  2. What is the electronic configuration of a copper atom?

    • [Ar] 3d10 4s1
    • [Ar] 3d9 4s2
    • [Ar] 3d10 4s2
    • [Ar] 3d8 4s2

  3. What is the electronic configuration of the Fe2+ ion?

    • [Ar] 3d6
    • [Ar] 3d5
    • [Ar] 3d7
    • [Ar] 3d4 4s2

  4. What is a transition metal, according to the strict definition?

    • Any element with a full d subshell in its ground-state atom, such as zinc or copper
    • Any element that is a gas at room temperature, such as nitrogen, oxygen or a noble gas
    • Any metal in Group 1 or Group 2 of the periodic table, which are the s-block elements
    • A d-block element that forms at least one stable ion with an incompletely filled d subshell

  5. Why do transition metals show variable oxidation numbers?

    • The 4s and 3d electrons have similar energies
    • Transition metals form only +2 ions in all compounds
    • Only the 3d electrons are ever lost in reactions
    • Oxidation number depends only on the number of protons

  6. Which subshell loses electrons first when a d-block atom forms a cation?

    • Electrons are lost at random from either subshell
    • The 1s subshell, which is nearest the nucleus
    • The 3d subshell, before the 4s subshell
    • The 4s subshell, before the 3d subshell

  7. What is the oxidation state of manganese in MnO4-?

    • +4
    • +5
    • +7
    • +2

  8. What is the oxidation state of chromium in Cr2O7^2-?

    • +2
    • +6
    • +7
    • +3

  9. What is the oxidation state of vanadium in V2O5?

    • +4
    • +2
    • +3
    • +5

  10. What is the electronic configuration of the Ni2+ ion?

    • [Ar] 3d8 4s1
    • [Ar] 3d10
    • [Ar] 3d9
    • [Ar] 3d8

  11. What is the electronic configuration of the Cu2+ ion?

    • [Ar] 3d10
    • [Ar] 3d8 4s1
    • [Ar] 3d9
    • [Ar] 3d7

  12. How many d electrons does Cr3+ have?

    • 3
    • 6
    • 5
    • 4

  13. How many d electrons does Fe3+ have?

    • 6
    • 4
    • 3
    • 5

  14. How many d electrons does Sc3+ have?

    • 0
    • 1
    • 3
    • 2

  15. What is the electronic configuration of Ti2+?

    • [Ar] 3d0 4s2
    • [Ar] 3d2
    • [Ar] 3d4
    • [Ar] 3d1 4s1

  16. Why is the electronic configuration of chromium [Ar] 3d5 4s1 rather than 3d4 4s2?

    • A half-filled 3d subshell gives extra stability
    • The 4s electrons are more stable than 3d electrons in every case
    • The 3d subshell cannot hold four electrons
    • Chromium has an extra proton that changes the filling order

  17. What is the oxidation state of chromium in K2Cr2O7?

    • +3, because chromium is a Group 6 element
    • +6, because each K is +1 and each O is -2
    • +7, because it has the same oxidation state as manganese in MnO4-
    • +12, because there are two chromium atoms

  18. How many electrons are lost when Fe2+ is oxidised to Fe3+, and what changes in the d subshell?

    • Two electrons from 4s, leaving 3d6 unchanged
    • One electron, moving the d configuration from 3d6 to 3d5
    • No electrons are lost because the oxidation state is simply relabelled
    • Three electrons from 3d, leaving 3d3

  19. Which ion has the configuration [Ar] 3d4?

    • Mn2+
    • V2+
    • Fe2+
    • Cr2+

  20. Why does Zn not count as a transition metal under the strict definition?

    • Zn is a Group 2 element, so it is excluded
    • Zn has no d electrons at all in its atom
    • Zn forms only covalent compounds, so it cannot form ions
    • Zn2+ has a full 3d10 subshell

All Pearson Edexcel Chemistry quizzes