Lanthanide contraction is the phenomenon where the size of the lanthanide ions decreases moving left to right across the periodic table, even though atomic number increases. Learn about the atomic radius trend of the Lanthanide series and how it is caused by the poor shielding of the 4f electrons. Compare the Lanthanide Contraction with the D Block Contraction and see how it affects ionization energy and properties. The lanthanide contraction is the decrease in atomic and ionic radii of the lanthanide elements due to poor shielding of nuclear charge by the 4f electrons. It affects the chemistry and properties of the lanthanides and the following transition metals.
