Which of the following ions has the maximum magnetic moment?

Which element of the $3d$-series has the highest third ionisation enthalpy?

$A$ first row transition metal in its $+2$ oxidation state has a spin-only magnetic moment value of $3.86 \ BM$. The atomic number of the metal is

For the four consecutive transition elements $Cr, Mn, Fe,$ and $Co$,the correct order of stability of their $+2$ oxidation state is:

The number of unpaired electrons in $Mn^{2+}$ ion is

State whether the following statements are true or false:
$(i)$ Atomic size increases with an increase in the atomic number of elements.
$(ii)$ The electron gain enthalpy for noble gases is approximately zero.
$(iii)$ The first element of the actinoid series is $Th$ and the last element is $Lu$.
$(iv)$ The general electronic configuration of $d$-orbitals is always $(n-1)d^{1-10}ns^2$.