Which of the following compounds is the most acidic?

What is the general electronic configuration of actinoids?

The electronic configurations of bivalent europium and trivalent cerium are
(atomic number : $Xe=54, Ce=58, Eu=63$ )

The chemistry of the actinoid elements is not so smooth as that of the lanthanoids. Justify this statement by giving some examples from the oxidation states of these elements.

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

Identify all the correct statements for Lanthanide contraction.
$(A)$ The covalent properties of the Lanthanide metal hydroxides increase from $La$ to $Lu$.
$(B)$ The chemical reactivity decreases from $La$ to $Lu$.
$(C)$ $La(OH)_3$ is more basic than $Lu(OH)_3$.
$(D)$ $Zr$ and $Hf$ have about the same radius.
$(E)$ Separation of Lanthanides from one another is easy.