The $EAN$ of $Fe$ in $K_4[Fe(CN)_6]$ is

$EAN$ of the central metal in the complexes $K_2[Ni(CN)_4]$,$[Cu(NH_3)_4]SO_4$ and $K_2[PtCl_6]$ are respectively.

$a$. Answer the following questions:
$i$. Which element of the first transition series has the highest second ionisation enthalpy?
$ii$. Which element of the first transition series has the highest third ionisation enthalpy?
$iii$. Which element of the first transition series has the lowest enthalpy of atomisation?
$b$. Identify the metal and justify your answer:
$i$. Carbonyl $M(CO)_5$
$ii$. $MO_3F$

$[Co(NH_3)_x]Cl_3$ has $EAN$ of $Co=36$. What is the value of '$x$' $:-$

The effective atomic number of $[A(NH_3)_6]Cl_3$ is $33$. What is the atomic number of element $A$?

What is the $EAN$ of $Cr$ in $[Cr(SCN)_6]^{3-}$?