`Mg^(2+)` is smaller than `O^(2-)` in size, throgh both have same electronic configuration. Explain?

Explanation

To explain why `Mg^(2+)` is smaller than `O^(2-)` despite both having the same electronic configuration, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Electronic Configuration**:
- Magnesium (Mg) has an atomic number of 12, and its electronic configuration is `1s² 2s² 2p⁶ 3s²`. When it loses 2 electrons to form `Mg^(2+)`, it attains the electronic configuration of neon, which is `1s² 2s² 2p⁶`.
- Oxygen (O) has an atomic number of 8, and its electronic configuration is `1s² 2s² 2p⁴`. When it gains 2 electrons to form `O^(2-)`, it also achieves the electronic configuration of neon, `1s² 2s² 2p⁶`.

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