Which lanthanoid element has the electronic configuration $[Xe]4f^7 5d^1 6s^2$?

The lanthanoid that does $NOT$ show $+4$ oxidation state is

The first element of the rare-earth metals is:

Which is the last element in the series of the actinoids? Write the electronic configuration of this element. Comment on the possible oxidation state of this element.

$Ln$ (Lanthanide) $\xrightarrow{\text{With Halogen}} X$
$Ln$ (Lanthanide) $\xrightarrow{\text{Burn With } O_2} Y$
$Ln$ (Lanthanide) $\xrightarrow{\text{Heated with } N_2} Z$
$X, Y$ and $Z$ are respectively:-

Determine the correct $(T)$ and incorrect $(F)$ statements from the following:
$(a)$ The symbol for Lanthanum is $La$.
$(b)$ The name of the element $Lu$ is Lanthanum.
$(c)$ The electronic configuration of $La^{3+}$ and $Ce^{4+}$ contains $4f^0$.