The number of $f$ electrons in the ground state electronic configuration of $Np$ $(Z=93)$ is ....... .

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:

What is the effect of lanthanoid contraction in the lanthanoid series of elements with increasing atomic number?

Explain the size of actinoid elements and their ions.

Which one of the following is a radioactive lanthanide?

Rare-earth elements are exhibited by