Polarizing Power of Cations
This is a handout which I use in an advanced general chemistry course, but which could be used in an inorganic course as well. It is a mini-periodic table with common cations and their charge to size ratios expressed as Q/r2, where Q is in integer charges (+1, +2), and r is in Angstroms. Conveniently, Na+ is an easy to remember 1.0, and Al3+ and Be2+ are easy to remember values of 10. This corresponds to the polarizing power of these ions, and is a crude proxy for how covalent their interactions with a given anion tend to be.