Calculate the oxidation number of Ni ion `[Ni (H_(2)O_(6))_(6)]^(2+)]` .

Explanation

To calculate the oxidation number of the Ni ion in the complex \([Ni(H_2O)_6]^{2+}\), we can follow these steps:

### Step 1: Identify the components of the complex
The complex consists of a nickel ion (Ni) and six water molecules (H2O) acting as ligands.

### Step 2: Determine the charge of the complex
The overall charge of the complex is given as \(2+\).

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