â¼ Part A Learning Goal Rank the following five elements by ionization energy. To understand the trends of increasing and decreasing ionization energies within groups and periods of the periodic table of the elements. Rank from highest to lowest ionization energy. To rank items as equivalent, overlap them. View Available Hint(s) lonization energy is the energy needed to remove the first electron from a neutral atom. When we strip away the first electron, the result is a positive ion. The ionization energy is higher for atoms whose valence electrons are closer to the nucleus, and it decreases as the outer electrons get farther from the nucleus. Reset Help Highest Lowest