Show the formation of magnesium chloride by electron transfer. Write the name of the cation and anion present in the compound formed. (Atomic Number of Mg = 12, Cl = 17)
Generated by claude-sonnet-4-6 · 2026-06-15 06:48 · grounding rag
Model Answer
Mg has electronic configuration 2, 8, 2. It loses 2 electrons to form Mg²⁺.
Cl has electronic configuration 2, 8, 7. Each Cl atom gains 1 electron to form Cl⁻.
$$\text{Mg} \rightarrow \text{Mg}^{2+} + 2e^-$$
$$(2,8,2) \qquad (2,8)$$
$$\text{Cl} + e^- \rightarrow \text{Cl}^-$$
$$(2,8,7) \quad (2,8,8)$$
Since Mg releases 2 electrons and each Cl needs 1, two Cl atoms are required → MgCl₂ is formed.
- Cation: Magnesium ion (Mg²⁺)
- Anion: Chloride ion (Cl⁻)
Source: Chapter 3, Section 3.3 – How do Metals and Non-metals React?
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Explanation
- Examiners expect the electron transfer equations with electronic configurations written below each species — this is the standard format shown in the textbook (Fig. 3.6).
- Clearly state that two Cl atoms are needed because Mg loses two electrons.
- Name both the cation and anion explicitly — easy 1 mark if not missed.
- Avoid drawing dot-cross diagrams unless specifically asked; the transfer equations are sufficient here.