What is the Difference Between Lanthanide Contraction and Actinide Contraction?

Lanthanide contraction and actinide contraction refer to the gradual decrease in the size of lanthanide and actinide elements, respectively, as their atomic numbers increase. Both contractions occur due to the poor shielding of the nuclear charge by the respective orbitals (4f for lanthanides and 5f for actinides). However, there are some differences between the two:

1. Size of contraction: Actinide contraction is greater than lanthanide contraction. This is because the shielding effect of 5f orbitals in actinides is poorer than that of 4f orbitals in lanthanides, leading to a more significant decrease in atomic size.
2. Atomic number range: Lanthanide contraction occurs in elements with atomic numbers from 58 to 71, while actinide contraction occurs in elements with atomic numbers from 90 to 103.

In summary, the main difference between lanthanide contraction and actinide contraction is the extent of the decrease in atomic size, with actinide contraction being greater due to the poorer shielding effect of 5f orbitals compared to 4f orbitals.

Comparative Table: Lanthanide Contraction vs Actinide Contraction

The key difference between lanthanide contraction and actinide contraction lies in the magnitude of the contraction. Actinide contraction is greater than lanthanide contraction. Here is a table summarizing their differences:

Both lanthanide and actinide contractions refer to the decrease in atomic size with increasing atomic number in the respective series of elements. These contractions are a result of the shielding effect of electrons in the lower energy orbitals, which reduces the effective nuclear charge experienced by the electrons in the higher energy orbitals.