Question

After doing some research, I realized that ion size is commonly characterized by its ionic radius and not the ionic volume. Then, what about the volume of the ion particle?

We know that ions tend to dissocciate in water and the hydrated ion size will depend on the interaction with water. However, what will be the size and volume of the ion when it adsorps onto a charged surface in a scenario where a charged object is immersed in salt solution?

I am particularly curious about the ionic volume for OH^- and Ca^2+ in bulk/mobile state and adsorped state.

Answer 1

Ionic size is commonly characterized by its ionic radius, but when ions are hydrated in water or adsorbed onto a charged surface, their size and volume can change. The specific behavior of ions in these scenarios depends on various factors.

Step-by-step explanation:

Ionic size is commonly characterized by its ionic radius, which is a measure of the distance from the nucleus of the ion to its outermost electrons. However, when ions are hydrated in water or adsorbed onto a charged surface, their size and volume can change.

When ions are hydrated in water, they are surrounded by a hydration shell, which is a sphere of water molecules that keep the ions separated. The hydrated ion size depends on its interaction with water. For example, OH- and Ca2+ ions in their hydrated state will have larger sizes and volumes compared to their sizes in bulk/mobile state.

When ions adsorb onto a charged surface in a salt solution, their size and volume can also change. The specific adsorption behavior of ions onto a charged surface depends on various factors, such as the charge of the surface, the charge of the ion, and the concentration of ions in the solution.