Lanthanoids $(Ln)$ are well known for their $+3$ oxidation state. Which of the following statements is $NOT$ applicable to them?

Which one of the following statements concerning lanthanide elements is false?

The outer electronic structure of lawrencium (atomic number $103$) is

Elements in which $4f$ orbitals are progressively filled are called as

Determine whether the following statements are True $(T)$ or False $(F)$:
$(a)$ All actinoid elements have a $7s^1$ configuration.
$(b)$ All actinoid elements have a $7s^0$ configuration.
$(c)$ There are no electrons in the $7s$ orbital of actinoids.

Identify all the correct statements for Lanthanide contraction.
$(A)$ The covalent properties of the Lanthanide metal hydroxides increase from $La$ to $Lu$.
$(B)$ The chemical reactivity decreases from $La$ to $Lu$.
$(C)$ $La(OH)_3$ is more basic than $Lu(OH)_3$.
$(D)$ $Zr$ and $Hf$ have about the same radius.
$(E)$ Separation of Lanthanides from one another is easy.