Question

The effective atomic number of iron in ${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{3 - }}$ is?
(A) 34
(B) 36
(C) 37
(D) 35

Answer 1

In order to answer this question, you must be aware of the concepts of the coordinate compounds and also with the structural component. Use the general formula to determine the effective atomic number of iron in ${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{3 - }}$ and mark the correct answer.

Complete step-by-step solution: Effective atomic number (EAN), number that represents the total number of electrons surrounding the nucleus of a metal atom in a metal complex. It is composed of the metal atom’s electrons and the bonding electrons from the surrounding electron-donating atoms and molecules.
Effective atomic number (EAN) in a complex is defined as the total number of electrons present around the central metal ion.
Effective Atomic Number (EAN) = Atomic number (Z) – Oxidation number + 2 × (Coordination number)
We will Calculate the Effective atomic number using the above listed formula:
The Effective Atomic Number of the Given Complex = $26 - 3 + 12\, = \,$ $35$, ( $F{e^{ + 3}}$ oxidation state of $Fe$ is present in the given complex ).

Hence, the correct answer is Option (D).

Note: The effective atomic number ${Z_{eff}}$ , (sometimes referred to as the effective nuclear charge) of an atom is the number of protons that an electron in the element effectively 'sees' due to screening by inner-shell electrons. It is a measure of the electrostatic interaction between the negatively charged electrons and positively charged protons in the atom. The lowest energy electrons occupy the space closest to the nucleus, and electrons of higher energy are located further from the nucleus.