Question

The EAN of cobalt is the complex ion $\left[Co\right(en{)}_{2}C{l}_2{]}^{+}$ is :

• A. 27
• B. 36
• C. 33
• D. 35

Answer 1

Answer: (B)

36

Atomic number of cobalt is 27, Hence the ground electronic configuration is $3d^{7}4s^2$ and that of Co(III) is $3d^{6}4s^0$.

Hence EAN = 27-3+(4x2)+(2x2) = 36 (4 of ethylenediamine as it is a bidentate ligand and 2 for each Cl).

Therefore the correct option is B.