Periodic Classification

Question 1

Higher is the oxidation number of non-metal, more is [ acidic/basic] nature

Answer 1

acidic nature

higher the electronegativity ,higher will be acidic nature

Question 2

Trends of Ionic Radii in the Periodic Table

Answer 2

Across a Period (Left to Right)
• Cations: Decrease in size because the effective nuclear charge increases, pulling electrons closer.
• Anions: Also decrease across a period but are always larger than cations due to increased electron-electron repulsion.
• Example:
• Na^+ > Mg^{2+} > Al^{3+} (decreasing trend for cations)
• N^{3-} > O^{2-} > F^- (decreasing trend for anions)

Question 3

Trends of Ionic Radii in the Periodic Table

Down a Group (Top to Bottom)

Answer 3

• Ionic radius increases because additional electron shells are added, increasing atomic size.
• Example:
• Li^+ < Na^+ < K^+ < Rb^+
• F^- < Cl^- < Br^- < I^-

Question 4

Ionic Radii Trends in Aqueous Solutions

Answer 4

• In aqueous solutions, ions interact with water molecules through hydration.
• Cations with smaller radii and higher charge have stronger attraction to water molecules, making them more hydrated.
• Anions are less hydrated than cations due to weaker electrostatic attraction with water.

Examples of hydrated ionic radii in water:
• Cations: Li^+ > Na^+ > K^+ (due to stronger hydration energy of smaller ions).
• Anions: F^- > Cl^- > Br^- (fluoride has the highest hydration due to its small size and high charge density).

Question 5

Relationship Between Ionic Radii and Hydration Energy

Answer 5

• Hydration energy: The energy released when an ion is surrounded by water molecules.

• Smaller ions with high charge have higher hydration energy because they strongly attract water molecules.

• Cations with smaller radii have higher hydration energy than larger cations.

• Anions follow the same trend but have generally lower hydration energy than cations.

Trend Example:
Li^+ > Na^+ > K^+

Mg^{2+} > Ca^{2+} > Sr^{2+}