Discussion Forum



1)

Which of the following co-ordinate complexes is an exception to EAN rule?

(Given atomic number Pt=78, Fe=26, Zn=30, Cu=29)


A) $[Pt(NH_{3})6]^{4+}$

B) $[Fe(CN)_6]^{4-}$

C) $[Zn(NH_3)_4]^{2+}$

D) $[Cu(NH_3)_4]^{2+}$

Answer:

Option D

Explanation:

Effective Atomic Number (EAN) can be calculated by the following relation.

EAN= Z(atomic number of the metal) -number of electrons  lost in the ion formation + number of electrons  gained from the donor  atoms of the ligands.

 2062021251_c9.PNG

$[Cu(NH_3)_4]^{2+}$ is an exception of EAN rule.