The IUPAC name of the complex ion `[CoCl(NH_3)(NH_2CH_2CH_2NH_2)_2]^(2+)` is:

Options

A. Chloroamminethylenediaminecobalt(II) ion
B. Amminechloridoethylenediaminecobalt(III) ion
C. Amminechloridobis(ethylenediamine)cobalt(II) ion
D. Amminechloridobis(ethylenediamine)cobalt(III) ion

Explanation

To find the IUPAC name of the complex ion \([CoCl(NH_3)(NH_2CH_2CH_2NH_2)_2]^{2+}\), we will follow these steps:

### Step 1: Identify the ligands and their names
The complex contains the following ligands:
- \(NH_3\) is called "ammine".
- \(NH_2CH_2CH_2NH_2\) is called "ethylenediamine" (abbreviated as "en").

### Step 2: Count the number of each ligand
In the complex:
- There is **one** \(NH_3\) ligand.
- There are **two** \(NH_2CH_2CH_2NH_2\) ligands.

### Step 3: Determine the oxidation state of cobalt
Let the oxidation state of cobalt be \(x\). The overall charge of the complex is \(+2\).
- The charge from the ligands:
- \(NH_3\) is neutral (0).
- \(NH_2CH_2CH_2NH_2\) is also neutral (0).
- \(Cl\) has a charge of \(-1\).

Setting up the equation:
\[ x + (-1) + 0 + 0 = +2 \]
\[ x - 1 = 2 \implies x = +3 \]
Thus, the oxidation state of cobalt is \(+3\).

### Step 4: Write the ligands in alphabetical order
When naming the ligands, we consider their names:
- "ammine" (for \(NH_3\))
- "ethylenediamine" (for \(NH_2CH_2CH_2NH_2\))

In alphabetical order, "ammine" comes before "ethylenediamine".

### Step 5: Use the appropriate prefixes
Since there is one \(NH_3\) ligand, we simply use "ammine". For the two \(NH_2CH_2CH_2NH_2\) ligands, we use the prefix "bis":
- "bis(ethylenediamine)"

### Step 6: Combine the names and specify the metal and its oxidation state
The name of the complex will be:
- Ligands: "bis(ethylenediamine) ammine"
- Metal: "cobalt"
- Oxidation state: "III" (since cobalt is in the +3 oxidation state)

### Final IUPAC Name
Putting it all together, the IUPAC name of the complex ion is:
**bis(ethylenediamine)amminecobalt(III)**