An unknown element X has the following successive ionization energies (kJ·mol⁻¹): IE₁…
CHEMISTRY · Multi-part · A Level · Chemistry · Periodicity and periodic trends · Periodicity and periodic trends
Problem
An unknown element X has the following successive ionization energies (kJ·mol⁻¹):
IE₁ = 737 IE₂ = 1450 IE₃ = 7730 IE₄ = 10500
A second element Y lies immediately to the right of X in the same period of the periodic table.
(a) Deduce the most probable group number and ground-state electron configuration of element X. Explain your reasoning based on the ionization-energy data.
(b) Provide a qualitative explanation for the very large jump between IE₂ and IE₃ for element X.
(c) Compare the effective nuclear attraction experienced by a valence electron in element X with that in element Y, and justify any difference you predict.
(d) Predict which of the two elements, X or Y, will have the larger atomic radius. Support your answer with a coherent argument tied to the conclusions from parts (a) through (c).