When a magnesium atom encounters an oxygen atom in suitable conditions, a chemical reaction occurs, primarily involving the transfer of electrons between the two atoms, leading to the formation of an ionic compound, magnesium oxide (MgO).
Understanding the Reaction Between Magnesium and Oxygen
Magnesium ($\text{Mg}$) is an alkali earth metal, located in Group 2 of the periodic table. It has 2 valence electrons. Oxygen ($\text{O}$) is a non-metal, located in Group 16, and needs 2 electrons to complete its outer shell. The significant difference in their electronegativities drives the transfer of electrons from magnesium to oxygen.
This reaction is a classic example of the formation of an ionic bond, typically occurring during combustion or oxidation of magnesium.
The Electron Transfer Process
The core event when a magnesium atom reacts with an oxygen atom is the transfer of electrons. This process results in the formation of electrically charged particles called ions.
Based on the reference, when magnesium reacts with oxygen to form magnesium oxide, the magnesium atom loses two electrons to form the Mg$^{2+}$ cation, which has electronic configuration 2,8. The oxygen atom gains these electrons to form the O$^{2–}$ anion, with electronic configuration 2,8.
- Magnesium Atom ($\text{Mg}$): Initially neutral, with 12 protons and 12 electrons (electronic configuration e.g., 2, 8, 2). It readily gives up its 2 valence electrons.
- Oxygen Atom ($\text{O}$): Initially neutral, with 8 protons and 8 electrons (electronic configuration e.g., 2, 6). It needs 2 electrons to achieve a stable electron configuration.
The two electrons lost by the magnesium atom are gained by the oxygen atom.
Formation of Magnesium Oxide (MgO)
After the electron transfer, we have:
- Magnesium Cation ($\text{Mg}^{2+}$): A positively charged ion with 12 protons and 10 electrons (electronic configuration 2,8).
- Oxide Anion ($\text{O}^{2–}$): A negatively charged ion with 8 protons and 10 electrons (electronic configuration 2,8).
These oppositely charged ions are strongly attracted to each other by electrostatic forces, forming an ionic bond. In a larger scale reaction, these ions arrange themselves into a crystal lattice structure, characteristic of the ionic compound magnesium oxide ($\text{MgO}$).
Here's a simplified view of the change:
| Species | Initial State (Atom) | Change | Final State (Ion) | Electronic Configuration |
|---|---|---|---|---|
| Magnesium (Mg) | Neutral atom | Loses 2 electrons | Positively charged cation (Mg$^{2+}$) | 2,8 |
| Oxygen (O) | Neutral atom | Gains 2 electrons | Negatively charged anion (O$^{2–}$) | 2,8 |
The reaction can be summarized as:
$\text{Mg} (\text{atom}) + \text{O} (\text{atom}) \rightarrow \text{Mg}^{2+} + \text{O}^{2–} \rightarrow \text{MgO} (\text{ionic compound})$
In essence, the atoms transform into stable ions, which then combine to form magnesium oxide.
