What is the electronic configuration of $Ce$ $(Z = 58)$?

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

The ionic radius of $La^{3+}$ is $1.06 \ \mathop{A}\limits^o$. Which of the following is the closest value for the ionic radius of $Lu^{3+}$ in $\mathop{A}\limits^o$? $(Lu = 71, La = 57)$

If the ionic radius of $_{57}La^{3+}$ is $1.06 \ \mathring{A}$,then the ionic radius of $_{71}Lu^{3+}$ will be approximately close to which of the following values in $\mathring{A}$?

Which of the following hydroxides is the most basic?

Europium is