Answer to “would mg and s form an ionic bond”
Magnesium (Mg) and sulfur (S) form an ionic bond because Mg is a metal that readily forms a cation by losing electrons, while S is a nonmetal that forms an anion by gaining electrons; the electrostatic attraction between these oppositely charged ions yields the ionic compound magnesium sulfide, MgS.
Step 1: Identify valence electrons and typical ion charges
Magnesium is in Group 2, so it has 2 valence electrons. Sulfur is in Group 16, so it has 6 valence electrons. A stable noble-gas-like configuration is reached when Mg loses 2 electrons and S gains 2 electrons.
| Element | Valence electrons (group trend) | Most common ion formed | How stability is reached |
|---|---|---|---|
| Mg | 2 | \(\mathrm{Mg^{2+}}\) | Loses 2 electrons to achieve a filled outer shell in the preceding noble-gas core. |
| S | 6 | \(\mathrm{S^{2-}}\) | Gains 2 electrons to complete an octet in the valence shell. |
Step 2: Write the electron-transfer (half-reaction) viewpoint
- Magnesium oxidation (electron loss): \[ \mathrm{Mg \rightarrow Mg^{2+} + 2e^-} \]
- Sulfur reduction (electron gain): \[ \mathrm{S + 2e^- \rightarrow S^{2-}} \]
The transferred electrons cancel when the processes occur together, leaving oppositely charged ions that attract.
Step 3: Combine ions to obtain a neutral empirical formula
Ionic compounds are electrically neutral overall. A single \(\mathrm{Mg^{2+}}\) balances a single \(\mathrm{S^{2-}}\):
\[ (+2) + (-2) = 0 \]Therefore, the simplest ratio is \(1:1\), giving the empirical formula \(\mathrm{MgS}\). The lattice can be summarized as:
\[ \mathrm{Mg^{2+} + S^{2-} \rightarrow MgS(s)} \]Visualization: Electron transfer and ion pairing
Common checks and pitfalls
- Charge balance: ionic formulas must satisfy total charge \(= 0\); for \(\mathrm{Mg^{2+}}\) and \(\mathrm{S^{2-}}\), the smallest neutral ratio is \(1:1\).
- Octet logic: sulfur gains 2 electrons (not 1) to complete an octet, so \(\mathrm{S^{2-}}\) is expected in simple ionic bonding with Group 2 metals.
- Name vs formula: “magnesium sulfide” corresponds to \(\mathrm{MgS}\); subscripts come from charge balancing, not from valence electron counts alone.