$Ce$ $(Z=58)$ is a member of

What is the general electronic configuration of lanthanoids?

Determine whether the following statements are True $(T)$ or False $(F)$:
$(a)$ Actinoid contraction increases from one element to the next.
$(b)$ Actinoid contraction decreases from one element to the next.
$(c)$ Lanthanoid contraction occurs,but actinoid contraction does not occur.

Which lanthanoid element exhibits $+2$ and $+3$ oxidation states?

Discuss the trends in oxidation states shown by actinoids.

Which among the following elements is radioactive?