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

Which actinoid from the following has the smallest ionic size in the $+3$ oxidation state?

$4f^2$ electronic configuration is found in

State the $E^o$ values of lanthanoids and provide their reactions with the following: $(i)$ $H_2$,$(ii)$ Carbon,$(iii)$ Dilute acid,$(iv)$ Halogens,$(v)$ $O_2$,and $(vi)$ $H_2O$.

Arrange $Ce^{3+}$,$La^{3+}$,$Pm^{3+}$,and $Yb^{3+}$ in increasing order of size.

Which is not the correct statement? (At. nos. $Ce = 58, Lu = 71, La = 57, Yb = 70$)