What is the coordination number of Ag in the [Ag(CN)2]− ion?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 2
The coordination number of a metal ion is the number of ligand donor atoms bonded directly to it.
Ligands: two \( \ce{CN^-} \) ions inside the bracket, each a unidentate ligand that binds through one donor atom.
Donor atoms bonded to Ag: 2 × 1 = 2, so the coordination number of Ag in \( \ce{[Ag(CN)2]^-} \) is 2.
NCERT (2026-27 edition):
5.2 Definitions of Some Important Terms Pertaining to Coordination Compounds – “The coordination number (CN) of a metal ion in a complex can be defined as the number of ligand donor atoms to which the metal is directly bonded.”