The most common oxidation state of Lanthanoid elements is $+3$. Which of the following is likely to deviate easily from $+3$ oxidation state?

Which one of the following lanthanides exhibits $+2$ oxidation state with diamagnetic nature? (Given $Z$ for $Nd=60, Yb=70, La=57, Ce=58$)

Identify an actinoid element from the following.

Identify the correct actinide series from the following.

Consider the following two statements:
$Statement-I:$ Among $Mg, Al, Mg^{2+}, Al^{3+}$,the one having the smallest size is $Al^{3+}$.
$Statement-II:$ $Eu$ has an exceptionally high atomic radius among lanthanide elements.
The correct answer is:

Which statement is incorrect with reference to inner transition elements?