JEE MainChemistryClassification of Elements and Periodicity in Properties
The first, second and third ionization enthalpies (in kJ mol⁻¹ ) for two elements X and Y belonging to Period 3 are given below: Element IE₁ IE₂ IE₃ X 496 4562 6910 Y 737 1451 7733 Based on the given data, identify the most stable ions formed by X and Y that are isoelectronic with Neon, and the correct relationship between their ionic radii.
Options
- AStable ions are X ⁺ and Y ²⁺ , and ionic radius of X ⁺ > Y ²⁺
- BStable ions are X ⁺ and Y ²⁺ , and ionic radius of X ⁺ < Y ²⁺
- CStable ions are X ²⁺ and Y ⁺ , and ionic radius of X ²⁺ > Y ⁺
- DStable ions are X ²⁺ and Y ⁺ , and ionic radius of X ²⁺ < Y ⁺
Correct answer
A. Stable ions are X ⁺ and Y ²⁺ , and ionic radius of X ⁺ > Y ²⁺
Step-by-step solution
From the given data, element X shows a massive jump between IE₁ and IE₂ ( 496 to 4562 kJ mol⁻¹ ). This indicates that removing the second electron disrupts a stable noble gas core, meaning X has 1 valence electron. Thus, its most stable ion is X ⁺ . Element Y shows a massive jump between IE₂ and IE₃ ( 1451 to 7733 kJ mol⁻¹ ), indicating it has 2 valence electrons. Its most stable ion is Y ²⁺ . Since both elements belong to Period 3, X is Sodium ( Na ) and Y is Magnesium ( Mg ). Their stable ions X ⁺ and Y ²⁺ are is