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Ionisation energies and electron shellsEdexcel International A Level Chemistry: Flashcards

What these 12 flashcards ask

  • Define the first ionisation energy.
  • Write the equation for the second ionisation energy of magnesium.
  • Are ionisation energies exothermic or endothermic? Why?
  • Why does each successive ionisation energy increase?
  • What does a large jump in successive ionisation energies show?
  • How is the group of an element found from its successive ionisation energies?
  • Why does the first ionisation energy decrease down a group?
  • Why does the first ionisation energy generally increase across a period?
  • Why is the first ionisation energy of Al lower than Mg?
  • Why is the first ionisation energy of S lower than P?
  • What does the large jump after the 9th ionisation energy of sodium show?
  • Which three factors affect ionisation energy?

Exam questions on Ionisation energies and electron shells

  1. A data-analysis class is studying the ionisation energies of calcium, an element in Group 2 of the Periodic Table.
    Define the term first ionisation energy.2 marks
  2. An unidentified element X has the following successive ionisation energies, in kJ mol⁻¹: first 578, second 1817, third 2745, fourth 11 577 and fifth 14 842.
    Explain why the second ionisation energy of X is greater than its first ionisation energy.2 marks
  3. The first ionisation energies of Group 1 elements are, in kJ mol⁻¹: lithium 520, sodium 496 and potassium 419. The second ionisation energy of potassium is 3052 kJ mol⁻¹.
    Explain why the first ionisation energy decreases from lithium to potassium.3 marks
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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).