Question

What was the term proposed by Werner for the number of groups bound directly to the metal ion in a coordination complex?

• A. Primary valence
• B. Secondary valence
• C. Oxidation number
• D. Polyhedra

Hint:

In Werner’s theory, the secondary valence refers to the coordination number, i.e., the number of ligands directly attached to the metal ion.

Answer 1

The Correct Option is B

Step 1: Understanding Werner's Theory
In Werner’s theory of coordination compounds, he proposed the terms primary valence and secondary valence.

The primary valence refers to the oxidation state of the metal ion.
The secondary valence refers to the number of groups (ligands) directly bound to the metal ion in a coordination complex.

Step 2: Explanation of Other Options
Option (a) Primary valence is incorrect because it refers to the oxidation number, not the number of ligands attached to the metal.

Option (c) Oxidation number is incorrect because it refers to the charge of the metal ion, not the number of ligand bonds.

Option (d) Polyhedra refers to the shape of the coordination complex, not the number of ligands bound to the metal.

Step 3: Conclusion
Thus, the term proposed by Werner for the number of groups bound directly to the metal ion is secondary valence.