Four main-group elements a, b, c and d are highlighted in the outline of the Periodic Table below: a b d List these elements below by increasing ionization energy. For example, if a has the lowest ionization energy and b the next highest, then your list should start a, b,... Important: don't try to figure out exactly which elements are marked, and then use your knowledge of the properties of each specific element. You don't need to. You will also be marked wrong for any answer, correct or not, that can't be determined from only the rough location of each marked element in the Periodic Table. 0000 5