Ionisation energiesAQA A-Level Chemistry: Mind map

Exam questions on Ionisation energies

1. 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
2. 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
3. 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