Question

Effective atomic number rule is used to find______.

• A. geometry of complex
• B. number of isomers of complex
• C. number of possible ligands around metal ion in complex
• D. All of the above.

Answer 1

The correct option is C number of possible ligands around metal ion in complex

$EAN$ rule can be used to determine the number of possible ligands around a metal ion as the ligands are added to a metal ion until the number of electrons around the metal ion reaches to its nearest noble gas configuration.
According to sidgwick, ​
EAN=Number of electrons in central metal atom or ion​+Number of electrons donated by ligands​
$EAN$ = atomic number of nearest noble gas.
$EAN=Z-O.S+2\times C.N$
Z=atomic number of central metal atom
O.S=Oxidation state of central metal atom
C.N=coordination number of ligands.