Step 1: Understanding the Question:
For the given coordination compound, \([Co(NH_3)_6]Cl_3\), we need to determine two properties of the central metal atom, Cobalt (Co): its coordination number and its oxidation state.
Step 2: Key Formula or Approach:
- Coordination Number (CN): It is the total number of coordinate bonds formed by the central metal ion with the ligands. For simple monodentate ligands, it is simply the number of ligand molecules.
- Oxidation State (OS): It is the charge that the central metal atom would have if all the ligands were removed along with their shared electron pairs. We calculate it by balancing the charges of the complex ion and the counter-ions.
Step 3: Detailed Explanation:
First, let's analyze the compound \([Co(NH_3)_6]Cl_3\). It consists of a complex cation \([Co(NH_3)_6]^{n+}\) and three chloride anions \(Cl^-\).
To find the Coordination Number:
The central metal ion is Cobalt (Co).
It is bonded to six ammonia (\(NH_3\)) ligands.
Ammonia (\(NH_3\)) is a monodentate ligand, meaning each molecule forms one coordinate bond.
Therefore, the coordination number = (number of ligands) \(\times\) (denticity) = \(6 \times 1 = 6\).
To find the Oxidation State:
1. First, determine the charge of the complex ion. Since there are three chloride ions (\(Cl^-\)), each with a -1 charge, the total charge of the counter-ions is \(3 \times (-1) = -3\). To maintain overall neutrality, the complex ion \([Co(NH_3)_6]\) must have a charge of +3.
2. Let the oxidation state of Cobalt (Co) be \(x\).
3. The ammonia ligand (\(NH_3\)) is a neutral molecule, so its charge contribution is 0.
4. The sum of the oxidation states within the complex ion must equal its overall charge (+3).
\[ (\text{OS of Co}) + 6 \times (\text{charge of } NH_3) = +3 \]
\[ x + 6 \times (0) = +3 \]
\[ x = +3 \]
So, the oxidation state of Cobalt is +3.
Step 4: Final Answer:
The coordination number is 6, and the oxidation state is +3.