Ionization Energy Teamwork - Work in Pairs
Group Members: (Type your names here)
(Save in Ms. Smith’s Inbox in the designated class period. Save as Chpt 2_IETW_Last, Names.doc)
I would save a copy for yourself as well.
PART 1 – FIRST IONIZATION ENERGIES
1. Define Molar Ionization Energy.
2. Think about the way a mass spectrometer operates. Describe the basic steps involved and then
discuss how you might you might modify that apparatus to measure the ionization energy of an
3. Wiki has a table of molar ionization energies for the elements. The 1st through 10th columns refer to
the 1st electron removed, the 2nd electron removed… You task is to use Excel to construct a scatter
plot with Z=1-20 on the X axis and FIRST molar ionization energy on the Y. DO NOT do a line of best
fit. Have Excel connect the dots instead and today we are going to look at the inconsistencies in the
larger trends. Paste your graph below this question.
4. The theory is that it should be easier to remove an electron from a higher energy level because it is
further from the positive charge of the nucleus and the lower energy levels provide some shielding.
This explains the first big drop that you see in your graph from Z=2 to Z=3 (He to Li). Why is He (Z=2)
higher than H (Z=1)?
5. Your answer from question 4 also explains the increase that we see in the second energy level from
Z=3 (Li) to Z=10 (Ne). What does this graph tell you about the electron capacity of the first energy
level (Z=1 to Z=2) compared to the second level (Z=3 to Z=8)?
6. Now think about electron configurations and come up with an explanation for why it takes more
energy to ionize Be (Z=4) than it does B (Z=5).
7. Take a look at the 2p sublevel (Z=5 to Z=10). Think about the component x, y, and z orbitals. What
does this graph tell you about how the electrons fill in the orbitals of a p sublevel? Does the data for
the 3p confirm that theory?
PART 2 – SUCCESSIVE IONIZATION ENERGIES
8. Compare the terms first ionization energy and successive ionization energies.
9. Use the same wiki data table to create another graph. The X axis should be the successive ionization
energies for all 19 of potassium’s electrons and the Y should be the log of the molar ionization
energy). We use the log function because as more electrons are removed, the pull of the protons
holds the remaining electrons more tightly. So much so that we must use a logarithmic scale to
make sense (graphically) of the data. Paste your graph below this question.
10. Give the energy level and sublevel of the first 3 electrons being removed from potassium.
11. Use the graph to explain how it gives evidence for the number of electrons in each energy level.
12. Does your graph give evidence for sub-levels?
13. You can tell how many valence electrons an element has by looking for the first big jump in
successive ionization energies. Describe two ways the graph for aluminum would differ from the
one you made for potassium.