Read the following two statements
Statement I: Ionic radius of Li+ is greater than Mg++
Statement II: Lithium and magnesium can't form superoxide

Question

Thermal stability order of Group 1 hydroxides is:

Answer 1

To determine the correctness of the given statements, we need to analyze them based on chemical principles:

Statement I: Ionic radius of Li⁺ is greater than Mg⁺⁺
- Lithium (Li) belongs to Group 1 of the periodic table and loses one electron to form Li⁺ ion. Magnesium (Mg) is in Group 2 and loses two electrons to form Mg⁺⁺.
- The ionic radius generally decreases with an increase in positive charge because the same number of protons have to attract fewer electrons. Thus, a doubly charged Mg⁺⁺ ion would be smaller than the singly charged Li⁺.
- Since Li⁺ has fewer positive charges compared to Mg⁺⁺, it has a larger ionic radius.
- Hence, Statement I is correct.
Statement II: Lithium and magnesium can't form superoxide
- Superoxide formation occurs typically with larger alkali metals that have lower ionization energy and can stabilize the larger superoxide ion (O₂⁻).
- Lithium being a small cation, forms oxide (O²⁻) rather than superoxide due to size mismatch and higher charge density.
- Similarly, magnesium also forms oxides rather than superoxides because small size and high charge density make it unfavorable for superoxide stabilization.
- Thus, Statement II is correct.

After evaluating both statements, we can conclude that:

Both Statement I and Statement II are correct.

Answer 2

To determine the correctness of the given statements, we need to analyze them based on chemical principles:

Statement I: Ionic radius of Li⁺ is greater than Mg⁺⁺
- Lithium (Li) belongs to Group 1 of the periodic table and loses one electron to form Li⁺ ion. Magnesium (Mg) is in Group 2 and loses two electrons to form Mg⁺⁺.
- The ionic radius generally decreases with an increase in positive charge because the same number of protons have to attract fewer electrons. Thus, a doubly charged Mg⁺⁺ ion would be smaller than the singly charged Li⁺.
- Since Li⁺ has fewer positive charges compared to Mg⁺⁺, it has a larger ionic radius.
- Hence, Statement I is correct.
Statement II: Lithium and magnesium can't form superoxide
- Superoxide formation occurs typically with larger alkali metals that have lower ionization energy and can stabilize the larger superoxide ion (O₂⁻).
- Lithium being a small cation, forms oxide (O²⁻) rather than superoxide due to size mismatch and higher charge density.
- Similarly, magnesium also forms oxides rather than superoxides because small size and high charge density make it unfavorable for superoxide stabilization.
- Thus, Statement II is correct.

After evaluating both statements, we can conclude that:

Both Statement I and Statement II are correct.

The Correct Option is A