Which of the following is a correct formula for calculation of EAN (Effective atomic number)?

EAN = Z - (O.N) + 2(C.N.)

where Z = Atomic number

O.N. = Oxidation number

C.N. = Co-ordination number

The correct answer is option 3. EAN = Z - (O.N) + 2(C.N.)

where Z = Atomic number

O.N. = Oxidation number

C.N. = Co-ordination number

Transition metal form coordination compounds very readily because they have vacant 'd' orbitals which can accommodate electron pairs donated by ligands. Metal ion in the complex tends to attain nearest stable inert gas configuration by gaining electrons from ligands.

Effective atomic number is given by

EAN = Z - (O.N) + 2(C.N.) or number of lone pairs donated to the central atom

where Z = Atomic number

O.N. = Oxidation number

C.N. = Co-ordination number