How do you determine first ionization energy? Can you tell by looking at the periodic table?

1 Answer
Jun 27, 2016

How else but by experiment?


The first ionization energy is determined by the energy of the following reaction:

#E(g) + Delta rarr E^+(g) + e^-#

Ionization energies INCREASE across a Period (from left to right as you face the table), and DECREASE down a Group. The rationalization behind this phenomenon underlies our ideas regarding Periodicity.