Which one of the following elements shows the maximum number of different oxidation states in its compounds?

The point of dissimilarity between lanthanides and actinides is

Determine the correct $(T)$ and incorrect $(F)$ statements from the following:
$(a)$ $Lu^{3+}$ and $Yb^{2+}$ are not paramagnetic.
$(b)$ Sheets are made from mischmetal.
$(c)$ Pipes are made from mischmetal.

Match the properties given in List-$I$ with the elements given in List-$II$:

List-$I$ (Property)	List-$II$ (Element)
$(A)$ Lanthanoid showing $+4$ oxidation state	$(i)$ $Pm$
$(B)$ Lanthanoid showing $+2$ oxidation state	$(ii)$ $Ce$
$(C)$ Radioactive lanthanoid	$(iii)$ $Lu$
$(D)$ Lanthanoid with $4f^7$ configuration in $+3$ state	$(iv)$ $Eu$
$(E)$ Lanthanoid with $4f^{14}$ configuration in $+3$ state	$(v)$ $Gd$
-	$(vi)$ $Dy$

Which of the following properties decreases on moving from $Ce$ to $Lu$?

Identify the ion having $4f^6$ electronic configuration.