Which element from the following has a half-filled $f$ orbital in the $+3$ oxidation state?

Provide the primary differences (comparison) between Lanthanoids and Actinoids.

Which of the following elements belongs to the inner transition elements?

The Lanthanoid contraction is responsible for the fact that

The electronic configuration of Curium (Atomic number $96$) is

Given below are two statements:
Statement $I$: In the Lanthanoids,the formation of $Ce^{+4}$ is favoured by its noble gas configuration.
Statement $II$: $Ce^{+4}$ is a strong oxidant reverting to the common $+3$ state.
In the light of the above statements,choose the most appropriate answer from the options given below: