Question

Fill in the blanks:
According to Werners 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)

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 $\left[ Cu \left( NH _{3}\right)_{4}\right] SO _{4}$ 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 $2$ .