The early lanthanide elements introduce occupation of the 4f subshell
CHEMISTRY · Multi-part · CBSE · Chemistry · d- and f-Block Elements · d- and f-Block Elements
Problem
The early lanthanide elements introduce occupation of the 4f subshell, yet their chemistry and periodic trends often resemble one another closely.
Answer the following questions about cerium (Z = 58) and the neighboring lanthanides using principles of atomic structure.
(a) Write the noble-gas abbreviated ground-state electron configuration for cerium.
(b) Cerium commonly forms a Ce4+ ion. Write the complete electron configuration for this ion and identify which subshells lose electrons during ion formation.
(c) For both Ce3+ and Ce4+, discuss how effective nuclear charge experienced by a 4f electron differs, and explain the consequence for the relative sizes (ionic radii) of the two ions.
(d) Across the series from lanthanum (Z = 57) to neodymium (Z = 60), atomic radii decrease only slightly even though additional protons are added to the nucleus. Using your understanding of 4f electron shielding, explain this so-called "lanthanide contraction."