Dave Doherty • Bitwixt Software Systems LLC www.bitwixt.com @Atomsmith1 @AtomsNMolecules August 03 Energy vs. Force In the lower left corner of figures 1 & 2, it states that the ionization energy is proportional to the Coulomb force. This is not correct. The ionization energy is equal to the difference between the: • energy of the bound electron and • energy of the unbound electron This is different from the forces in these two situations. It's a pretty common error to confuse potential energy and force. In the Coulomb's Law case: F ~ Q₁Q₂ / r² (force) E ~ Q₁Q₂ / r (energy) If you want to understand the difference between potential energy and force: Simply put, the force is the first derivative of the energy. (Negative of it, if you really care.) If you think of a typical potential energy plot, the points on the curve are the energies at various distances. The slopes (first derivatives) at various points on the curve are the forces. Where the curve is steep, the force is high. Where the curve is flat, the force is low.
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Energy vs. Force
• energy of the bound electron