Question

Differentiate between lanthanoids and actinoids.

Answer 1

Hint : Lanthanoids and actinoids are elements that are placed in the lanthanide and actinide series of the periodic table. Both the series are included under $f-$ block elements of periodic table.

Complete answer:
> These elements are in $f-$ block because their valence electron enters in $f$ orbitals.
> Lanthanoids and actinoids form a group that is almost disconnected from the periodic table as they are placed on the bottom of the table. These are some main differences between lanthanoids and actinoids given below.

Lanthanide	Actinoids
In lanthanide the filling of $$4f$$ orbitals take place.	In action the filling of $$5f$$ orbitals take place.
This series includes elements from atomic number $57$ to $71$.	This series includes elements from atomic number $89$ to $103$.
These elements are non-radioactive except promethium.	All the elements of this series are radioactive.
Binding energy of $$4f$$ orbitals is higher.	Binding energy of $$5f$$ orbitals is higher.
Lanthanoids have a low tendency to form complexes.	Actinoids show greater tendency to form complexes.
Besides $+3$ oxidation number it also shows $+2$ and $+4$ oxidation state in few compounds.	Besides $+3$ oxidation number it also shows $+4,+5$ and $+7$ oxidation state in few compounds.
Lanthanoids have a bright and silvery appearance.	Most of the actinides ions are deeply coloured.

Note : So we have learned some main difference between lanthanoids and actinoids above. Hence Lanthanoids and actinoids are f block elements of the periodic table. They are metal but soft .They have different chemical properties. We can say that the main difference between the elements of the both series is that actinoids can form complexes easily whereas lanthanoids do not form complexes easily.