(i) Write the electron-dot structures for sodium, oxygen and magnesium.
(ii) Show the formation of `Na_(2)O` and `M_(g)O` by the transfer of electrons.
(iii) What are the ions present in these compounds?

Explanation

### Step-by-Step Solution

#### (i) Write the electron-dot structures for sodium, oxygen, and magnesium.

1. **Sodium (Na)**:
- Sodium has an atomic number of 11, which means it has 11 electrons. The electronic configuration is 2, 8, 1.
- The valence shell (outermost shell) has 1 electron.
- **Electron-dot structure**: Na· (one dot representing the single valence electron).
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