Question

Magnesium reacts with an element (X) to form an ionic compound. If the ground state electronic configuration of (X) is 1s² 2s² 2p³ , the simplest formula for this compound is

• A. Mg₂X₃
• B. Mg₂X
• C. MgX₂
• D. Mg₃X₂

Answer 1

The Correct Option is A

To determine the simplest formula for the compound formed by the reaction between magnesium (Mg) and element X with the given electron configuration, we need to understand the valency of each element involved.

1. Electronic Configuration of Element X:
   The ground state electronic configuration of element X is given as \(1s^2 2s^2 2p^3\). From this configuration, it is evident that X has 5 electrons in its valence shell (2s and 2p orbitals), which makes it belong to group 15 of the periodic table. Hence, X is likely to be nitrogen (N).
2. Determination of Valency:
   • Magnesium (Mg): Magnesium is in group 2 of the periodic table with an electronic configuration of \(1s^2 2s^2 2p^6 3s^2\). It has two electrons in its outer shell and a valency of +2, as it loses two electrons to achieve a noble gas configuration.
   • Nitrogen (N): Nitrogen needs three additional electrons to fill its valence shell (completing the p orbital). Therefore, it commonly exhibits a valency of -3.
3. Forming the Compound:
   • To form a neutral compound, the total positive charge from magnesium ions must balance the total negative charge from nitrogen ions.
   • Magnesium ions contribute a charge of +2 each (2 \times \text{positive charge}) and nitrogen ions a charge of -3 each (3 \times \text{negative charge}).
   • The simplest way to balance these charges is to use three Mg²⁺ ions and two N^3- ions, resulting in Mg₃N₂.
4. Conclusion: The simplest formula of the ionic compound formed by magnesium and nitrogen is Mg₃N₂.

Therefore, the correct option given is Mg₃X₂. The options in the question seem to contain an error, as Mg₃X₂ matches our derived formula based on the provided reasoning.