Answer: Lower oxidation states being more stable (e.g., Pb 2+ more stable than Pb 4+ ).
- A Lower oxidation states being more stable (e.g., Pb<sup>2+</sup> more stable than Pb<sup>4+</sup>)
- B Higher oxidation states such as Pb<sup>4+</sup> becoming the preferred state
- C All oxidation states being equally stable with no preference shown
- D A complete absence of any preferred oxidation state for these elements
Correct answer: A. Lower oxidation states being more stable (e.g., Pb<sup>2+</sup> more stable than Pb<sup>4+</sup>)
Explanation: The inert pair effect stabilises ns<sup>2</sup> electrons in heavy p-block elements, making the lower oxidation state (ns<sup>2</sup> retained) more stable.
Xenon tetrafluoride (XeF4) has six electron domains around xenon — four Xe–F bonds plus two lone pairs. The lone pairs occupy opposite axial positions, leaving the four fluorine atoms in a square-planar shape (Xe–F ≈ 194 pm). Image: ChemSim, Public Domain, via Wikimedia Commons.
Concept context
Covers the nitrogen family (Group 15), oxygen family (Group 16), halogens (Group 17), and noble gases (Group 18). One of the highest-weightage inorganic chapters in NEET and JEE - includes preparation and properties of HNO₃, H₂SO₄, interhalogens, and xenon compounds.