Question

According to Werner's coordination theory, there are _______ kinds of valency, _______ and ______. The primary valency of a central metal ion is satisfied with ________.

• A. three, negative, positive, cations
• B. different, negative, positive, anions
• C. two, primary, secondary, anions
• D. two, saturated, unsaturated, cations

Answer 1

Answer: (C)

two, primary, secondary, anions

According to Werner's coordination theory, there are two kinds of valency, primary and secondary. The primary valency of a central metal ion is satisfied with anions.

For example, in $\left[Cu\right(N{H}_3{)}_4]S{O}_4$ primary valency is 2 and secondary valency is 4.

Secondary valence refers to coordination number. Since copper is coordinated to 4 ammonia ligands, secondary valence is 4. Primary valence is satisfied by anions. Since sulphate ion has $-2$ charge, primary valence is 2.