Answer: Na+.
- A Na+
- B CN-
- C NH<sub>3</sub>
- D Cl-
Correct answer: A. Na+
Explanation: Na+ has no lone pairs to donate; it cannot act as a ligand. CN-, NH<sub>3</sub>, and Cl- all have lone pairs.
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.