Question

Which of the following compounds have effective atomic number equal to the atomic number of a noble gas ?

• A. $K\left[Co\right(CO{)}_4]$
• B. $K_2\left[Fe\right(CO{)}_4]$
• C. $\left[CoC{l}_3\right(H_{2}O{)}_3]$
• D. All of the above

Answer 1

The correct option is D All of the above

$EAN=Z-X+Y$
$Z=$ Atomic number of the metal
$X=$ Oxidation state of metal ion
$Y=$ Number of electrons donated by the ligands

$\left(A\right)\text{For}\left[Co\right(CO{)}_4]$
$EAN=Z-X+Y=27+1+8=36$

$\left(B\right)\text{For}{K}_2\left[Fe\right(CO{)}_4]$
$EAN=26+2+8=36$
This is equal to the atomic number of krypton.

$\left(C\right)\text{For}\left[CoC{l}_3\right(H_{2}O{)}_3],EAN=27-3+12=36$
This is equal to the atomic number of krypton.