Ionisation energiesAQA A-Level Chemistry: Flashcards
What these 12 flashcards ask
- Define first ionisation energy.
- Write the equation for the first ionisation energy of sodium.
- Write the equation for the second ionisation energy of calcium.
- Why do successive ionisation energies increase?
- What does a large jump in successive ionisation energies show?
- How can successive ionisation energies identify the group?
- Why does first ionisation energy generally increase across Period 3?
- Why is the first ionisation energy of Al lower than Mg?
- Why is the first ionisation energy of S lower than P?
- What is the trend in first ionisation energy down Group 2?
- Why does first ionisation energy decrease down Group 2?
- What two Period 3 dips give evidence for sub-shells?
Exam questions on Ionisation energies
- Compounds of Group 2 metals are used in fireworks and in building materials. The first ionisation energies of the Group 2 metals decrease from beryllium to barium. Calcium has a first ionisation energy of 590 kJ mol⁻¹ and a second ionisation energy of 1145 kJ mol⁻¹.Explain why the second ionisation energy of calcium is greater than its first ionisation energy.2 marks
- A chemist is given the successive ionisation energies, in kJ mol⁻¹, of two unknown elements, X and Y, which are both in the first three periods of the periodic table. X: 496, 4563, 6913, 9544. Y: 738, 1451, 7733, 10543.Deduce the group in which element Y is found. Give a reason for your answer.2 marks
- The first ionisation energies, in kJ mol⁻¹, of the Period 3 elements from sodium to argon are: Na 496, Mg 738, Al 578, Si 786, P 1012, S 1000, Cl 1251 and Ar 1521.Explain why the first ionisation energy of aluminium is lower than that of magnesium.3 marks
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).