Polarizability and Polarizing Power

[Stella Nguyen 1J]

Hi everyone!

I was wondering if you guys could explain to me what polarizability is and how we would determine what has a bigger polarizing power when comparing cations or anions? I didn't really understand this concept.

Thank you so much!

[Jagveer 1I]

Polarizability is the ability to which a species of electrons can be distorted. If they can be easily distorted, they have a higher polarizability. Polarizability depends on the size of the molecule and therefore the number of electrons. The less tightly the electrons are held, the more polarizable it is. Hope this helps.

[David Chibukhchian 2G]

I would also add that cations become more polarizing (or better at distorting the cloud of the anion it gets near) when they're smaller and have a more positive charge. This means that as you move up and to the right on the periodic table, cations become more polarizing. Meanwhile, anions become more polarizable as they get larger, and this is because their electrons are further away and thus easier to distort. That is basically the trend that we see for this topic, I hope that helps!

[Samiha Molla 3G]

Polarizability is how much an anion's electron cloud can be distorted. Bigger atoms are more polarizable because they are less electronegative, so their electrons are less tightly held and more likely to be distorted by another atom's electron cloud.
Polarizing power is how much a cation can distort an anion's electron cloud. Smaller, highly charged atoms have more polarizing power because they can pull harder on the other atom's electrons. Hope this helps!

[Anna_Mohling_1D]

In addition to what everyone else said, I find it really helpful to just know that polarizing power is related to cations and polarizability is related to anions!

[Frankie Mele 3J]

The polarizing power of cations increases as the cation becomes smaller and more highly charged. The polarizability of anions increases as the anion become larger and less electronegative.