Ionization Energy and the Periodic Table

 The periodic table organizes the elements according to their increasing atomic number. This is useful because repeating patterns of physical and chemical properties occur as the atomic number of the elements increases. This is called the periodic law.

 Ionization Energy is the amount of attraction an atom has for its own electrons. An element with a high ionization energy attracts its own electrons very strongly. It is not likely to release electrons to participate in chemical reactions. An element with a low ionization energy gives up electrons easily. It is more likely to participate in chemical reactions. Thus, the ionization energy of each element gives us one measure of its reactivity compared to other elements.

 This information is particularly useful in predicting how each metallic element will behave chemically. Ionization energy is not as useful for predicting the chemical activity of nonmetals and metalloids. They are more likely to accept or share electrons in chemical reactions rather than to give up their electrons. In this activity you will examine how the ionization energy varies as the atomic number increases.

 Procedure:

1.    Study the chart of ionization energies and electronegativies found below.   The units for ionization energy on this chart are kilojoules/mole.   

2.    If you are plotting this graph by hand turn the paper horizontally. The x-axis is the atomic number and should go to 92 (uranium). The y-axis is ionization energy (kJ/mol) and should go from 0 to

3.    Write out in words your conclusions from the graph.