The first-ionization energies (in kJ·mol⁻¹) for elements with atomic numbers 3–10 are…
CHEMISTRY · Subjective · A Level · Chemistry · Periodicity and periodic trends · Periodicity and periodic trends
Problem
The first-ionization energies (in kJ·mol⁻¹) for elements with atomic numbers 3–10 are as follows:
Z = 3 520 Z = 4 900 Z = 5 801 Z = 6 1086 Z = 7 1402 Z = 8 1314 Z = 9 1681 Z = 10 2081
Describe the evidence in these data that ionization energy is periodic, and explain why the value for Z = 5 is lower than that for Z = 4, even though nuclear charge increases.