Find the oxidation number of Ni in `K_4 [Ni(CN)_4]`

Explanation

To find the oxidation number of Nickel (Ni) in the complex ion \( K_4[Ni(CN)_4] \), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the components of the compound**:
- The compound consists of potassium ions (K\(^+\)) and the complex ion \([Ni(CN)_4]^{2-}\).

2. **Determine the charge of potassium ions**:
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