A chemist investigates an element X in the gas phase
CHEMISTRY · Multi-part · A Level · Chemistry · Periodicity and periodic trends · Periodicity and periodic trends
Problem
A chemist investigates an element X in the gas phase. The first five successive ionization energies of X are listed below.
IE₁ = 738 kJ·mol⁻¹ IE₂ = 1451 kJ·mol⁻¹ IE₃ = 7733 kJ·mol⁻¹ IE₄ = 10544 kJ·mol⁻¹ IE₅ = 13630 kJ·mol⁻¹
Answer the questions that follow.
(a) Identify the group (family) in the periodic table to which element X most likely belongs. State your reasoning based on the pattern in the successive ionization energies.
(b) Write the complete ground-state electron configuration of the neutral atom of X.
(c) Explain, in terms of effective nuclear charge and atomic radius, why IE₃ is dramatically larger than IE₂.
(d) Predict whether the atomic radius of X is greater than, less than, or approximately equal to that of the element immediately to its right in the same period. Provide a justification based on periodic trends and Coulombic considerations.