Question

Compare Lanthanide and Actinide? (Write any five points).

Answer 1

Lanthanides and actinides lie in the f-block of the periodic table. The elements in the lanthanide and actinide have incompletely filled f-orbitals. Lanthanides have incompletely filled 4f-orbital whereas actinides have incompletely filled 5f-orbitals.

Complete step-by-step answer: We know that lanthanides and actinides lie in the f-block of the periodic table. The elements in the lanthanide and actinide have incompletely filled f-orbitals. Lanthanides have incompletely filled 4f-orbital whereas actinides have incompletely filled 5f-orbitals.
We can compare lanthanides and actinides based on the properties like electronic configuration, atomic and ionic sizes, oxidation states, chemical reactivity and ability to form complexes.
The comparison between lanthanides and actinides is as follows:

Property	Lanthanide	Actinide
Electronic configuration	The lanthanide elements have general electronic configuration $[{\text{Xe}}]4{f_{1 - 14}}5{d_{0 - 1}}6{s_2}$.	The actinide elements have general electronic configuration $[{\text{Rn}}]5{f_{1 - 14}}6{d_{0 - 1}}7{s_2}$.
Atomic and ionic sizes	The atomic and ionic size decreases as the atomic number increases. This is because positive charge increases and the effective nuclear charge increases.	The atomic and ionic size decreases as the atomic number increases. This is because positive charge increases and the effective nuclear charge increases.
Oxidation states	Most lanthanides have $+ 3$ oxidation state while some show $+ 2$ and $+ 4$ oxidation state.	Most actinides have $+ 3$ oxidation state while some show $+ 4$ and $+ 5$ oxidation state.
Chemical reactivity	Lanthanides are less electropositive than actinides and thus they are less reactive than actinides.	Actinides are more electropositive than lanthanides and thus they are more reactive than lanthanides.
Ability to form complexes	Lanthanides form coordination complexes.	Actinides do not form coordination complexes.

Note: Actinides are radioactive in nature but lanthanides are stable than actinides and thus form coordination complexes. The atomic number of lanthanides is from 57-71 and the atomic number of actinides is from 89 to 103.