The question is about identifying the correct representation of a complex ion. Let's break it down step-by-step to determine why the given option is correct:
Understanding Complex Ions: In coordination chemistry, a complex ion consists of a central metal atom/ion that is bonded to a set of molecules or anions, termed ligands. The notation typically lists the central atom first, followed by the ligands.
Correct Representation in Complexes: - A complex should list its ligands in a specific order: neutral ligands are usually listed first followed by anionic ligands. - Within each category (neutral or ionic), ligands are usually ordered alphabetically. - In the given options, \([Co(NH_3)_4(H_2O)Cl]^{2+}\) follows this rule, listing the neutral ligands \(NH_3\) and \(H_2O\) before the anionic ligand \(Cl^{-}\).
Analyzing Options:
\([Co(H_2O)(NH_3)_4Cl]^{2+}\) - Lists \(H_2O\) before \(NH_3\) which doesn't follow the alphabetical criterion within the neutral ligands.
\([CoCl(H_2O)(NH_3)_4]^{2+}\) - Lists the anionic ligand \(Cl^{-}\) first which is incorrect according to the standard coordination compound representation.
\([Co(NH_3)_4Cl(H_2O)]^{2+}\) - Incorrect because \(Cl^{-}\) should be listed after the neutral ligands.
\([Co(NH_3)_4(H_2O)Cl]^{2+}\) (Correct Option) - This follows the correct order: neutral ligands \(NH_3\), \(H_2O\), then the anionic ligand \(Cl^{-}\).
Conclusion: The correct representation of the complex ion as per standard chemical notation is \([Co(NH_3)_4(H_2O)Cl]^{2+}\), which follows all the rules of chemical nomenclature for complexes.