The number of elements from the following that do not belong to lanthanoids is:
$Eu, Cm, Er, Tb, Yb$ and $Lu$

Name the members of the lanthanoid series which exhibit $+4$ oxidation state and those which exhibit $+2$ oxidation state. Try to correlate this type of behavior with the electronic configurations of these elements.

What is the maximum oxidation state of $Th$?

The trivalent ion having the largest size in the lanthanide series is:

Identify an actinoid element from the following.

Which element from the following has the largest ionic size in the $+3$ state?