Cause of Lanthanide Contraction

As the atomic number increases across the lanthanide series, the nuclear charge increases, and the 4f electrons poorly shield the outer shell electrons, leading to a greater effective nuclear charge and a decrease in atomic and ionic radii.

Increasing nuclear charge
Poor shielding effect of 4f electrons
Decrease in atomic and ionic radii

The lanthanide contraction affects the properties and chemistry of the lanthanides, making their separation easier, but it also influences the post-lanthanide elements, making their separation more difficult.

Influence of Electron Shielding

The influence of electron shielding effect on Lanthanide Contraction can be:

The poor shielding effect of the 4f electrons causes Lanthanide Contraction.
The 4f electrons shield the outer shell electrons less effectively than s, p, and d electrons.
As a result, the effective nuclear charge increases, and the atomic and ionic radii decrease.
The shielding effect is less effective in the lanthanide series due to the filling of the 4f subshell located near the nucleus.
The poor shielding effect produces a greater-than-expected decrease in atomic and ionic radii.
The shielding effect is a fundamental concept in chemistry, where inner shell electrons protect outer shell electrons from the positive charge of the nucleus.

Lanthanide Contraction

Lanthanide Contraction is a phenomenon that describes the steady decrease in the size of the atoms and ions of the rare-earth elements as the atomic number increases. The lanthanide contraction is a significant factor in the close chemical similarity of the rare-earth elements and affects the properties of the post-lanthanide elements. This phenomenon has implications for various properties, such as atomic size, density, and chemical reactivity.

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