The table below lists the first six ionization energies of an element that is known…
CHEMISTRY · Multi-part · A Level · Chemistry · Periodicity and periodic trends · Periodicity and periodic trends
Problem
The table below lists the first six ionization energies of an element that is known to be located within the first three periods of the periodic table.
Ionization step (n) 1 2 3 4 5 6
Ionization energy (kJ mol⁻¹) 738 1451 7733 10542 13630 18000
Answer the following questions about the element and the observed pattern of its successive ionization energies.
(a) Identify between which two successive ionizations the largest increase in required energy occurs.
(b) Using your answer to part (a), determine the number of valence electrons in the neutral atom and propose the most likely identity of the element (atomic number ≤ 20).
(c) Provide a particulate-level explanation, in terms of electron configuration, shielding, and effective nuclear charge, for why the sharp increase in energy occurs at that particular step.