Question

Write one similarity and one difference between the chemistry of Lanthanides and that of actinides:

Answer 1

Lanthanides and actinides both are f-block elements. The f-orbitals in lanthanides are deeply buried, so does not affect the ligand field. The f-orbitals in actinides get affected by the ligand field.

Complete step by step answer:
The element having electrons in (n - 2) f orbital are known as the f-block element.
Lanthanides and actinides both are f-block elements.
The elements from the atomic number 58 - 71 are known as lanthanides and the elements from the atomic number 58 - 71 are known as actinides.
The similarity in between lanthanides and that of actinides is as follows:
Both are inner transition elements and the last electron enters in (n - 2) f-orbital in both lanthanides and that of actinides.
The difference in between lanthanides and that of actinides is as follows:
The lanthanides show a few oxidation states whereas the actinides show a large oxidation number just like transition metals. Because the 4f orbitals are more attracted by the nucleus than the 5f orbitals, so it is hard to remove an electron from 4f orbitals of lanthanides. In lanthanides, the energy difference between 4f and 5d orbitals is large whereas the energy difference between 5f and 6d orbitals is low.
The most common oxidation state shown by lanthanides is + 3 whereas the actinides shows + 2, + 3, + 4, + 5, + 6, + 7 oxidation states.

Note: Due to the high energy difference between 4f and 5d orbitals, the lanthanides involved in ionic bonding whereas the actinides involved in covalent bonding like transition metals. Because in lanthanides the 4forbitals are deep buried so, these orbital are not affected by ligand field so, lanthanides show sharp spectra for f-f transition whereas the actinides show broad spectra for f-f transition.