Which of the following is arranged in order of increasing radius? — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: In the gaseous state, the ionic sizes follow the order: Li^+ < Na^+ < K^+. Step 2: When placed in water, the smallest ion (Li^+) has the highest charge density, which strongly attracts water molecules and forms the largest hydration shell. Step 3: Thus, the hydrated ionic radius is inversely proportional to the gaseous ionic radius, leading to the order: K^+(aq) < Na^+(aq) < Li^+(aq) (option a).