Number of unpaired electrons in $Mn^{2+}$ is

What is the atomic number of the first post-actinoid element?

Given below are two statements :
Statement $I$ : The higher oxidation states are more stable down the group among transition elements unlike $p-$block elements.
Statement $II$ : Copper can not liberate hydrogen from weak acids.
In the light of the above statements,choose the correct answer from the options given below :

The spin-only magnetic moment value of the compound with the strongest oxidizing ability among $MnF_{4}$,$MnF_{3}$,and $MnF_{2}$ is $............$ $B.M.$ [nearest integer]

Transition elements exhibit variable valencies because they release electrons from the following orbits:

$Ti^{2+}$ and $Ni^{2+}$ have .....