1. The problem statement, all variables and given/known data I was going through my past question and answer, I then came across this: "The noble gases have the highest ionization energies in each period". I then wondered why and how the above statement is a reality. How can the above statement be true when the noble gases have large atomic radi? 2. Relevant equations No equation is involved. 3. The attempt at a solution I know that Ionization energy, is the energy required to remove the outermost electron from a gasous atom. If you say that the noble gases has the highest Ionization energies, how true is that when you know that the noble gases have a relatively large atomic radius? I belive that the noble gases should have the lowest ionization energy since they have large atomic radius. This (lowest ionization energy) is possible because the larger the atomic radius the farer the distance of the outermost electron from the attraction of the nucleuos, thereby making it easier for outermost electron to escape. In such circustance, the outermost electron will leave with a very small energy. From my statement above, I have it that the noble gases have the lowest and not the highest ionization energy. If you the person viewing this my thread has a contrary view to mine on this concept on discusion feel free to share your own opinion. Let's see how we can collectively solve this problem.