Which of the following exhibits only $+3$ oxidation state?

Which among the following properties of lanthanoids is $NOT$ true?

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

In which of the following properties do $Lanthanoids$ and $Actinoids$ show similarity?

In $f$-block elements,which orbitals are progressively filled by electrons?

Which of the following lanthanoids shows $+4$ oxidation state to acquire noble gas configuration?
(At nos. : $La=57, Ce=58, Eu=63$ and $Yb=70$ )