The atomic number of the central metal atom can be determined by the EAN rule.
Given : metal carbonyl is M(CO)x where, M = metal x = 4
Thus, the metal carbonyl is M(CO)4The CO is a neutral ligand, having a lone pair of electrons.
It is a monodentate ligand.
Thus, electrons donated per ligand per donor atom = 2 Number of electrons donated by 4 CO molecule = 2 × 4 = 8 electrons.
According to the EAN rule, the ligands in the coordination sphere of a transition metal complex must provide the necessary number of electrons that will give the central metal ion the electronic configuration of a noble gas.
We know that,Effective atomic number (EAN) for M = Atomic number of M (Z) + Number of electrons donated by 4COLet EAN be 36 (Atomic number of krypton, a rare gas).
36 = Z + 8Z = 36 - 8 = 28
Therefore,Atomic number of M = 28
Hence, the correct option is (D).
Identify the correct orders against the property mentioned:
A. H$_2$O $>$ NH$_3$ $>$ CHCl$_3$ - dipole moment
B. XeF$_4$ $>$ XeO$_3$ $>$ XeF$_2$ - number of lone pairs on central atom
C. O–H $>$ C–H $>$ N–O - bond length
D. N$_2$>O$_2$>H$_2$ - bond enthalpy
Choose the correct answer from the options given below:
Consider the following sequence of reactions : 
Molar mass of the product formed (A) is ______ g mol\(^{-1}\).

In the first configuration (1) as shown in the figure, four identical charges \( q_0 \) are kept at the corners A, B, C and D of square of side length \( a \). In the second configuration (2), the same charges are shifted to mid points C, E, H, and F of the square. If \( K = \frac{1}{4\pi \epsilon_0} \), the difference between the potential energies of configuration (2) and (1) is given by: