Chem 31 SI 11/08/09
Periodic Properties
Quantum Numbers Warm Up:
1. Label the s, p, d, and f blocks on the periodic table below.
2. For an electrically neutral oxygen atom, there are 8 electrons, and each has its own unique set of atomic numbers.
Assign a viable set of atomic numbers (n, l, ml, ms) to each electron.
1)
5)
2)
6)
3)
7)
4)
8)
3. For n=3, there are18 possible electrons (2n2). Each electron has a unique set of quantum numbers. Map out the
possible configuration. Instead of l use s,p, or d. Instead of ml use an orientation subscript (example: Px, Py, Pz).
Instead of ms use ↑ or ↓. On the periodic table below, highlight or circle the n=3 ground state electron series.
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Chem 31 SI 11/08/09
Periodic Properties
Trends in Atomic Radius:
1. On the periodic table below, use arrows to show the general directions of increase in atomic radius moving
vertically and horizontally along the table.
2. Explain why the atomic radius of Helium is smaller than the atomic radius of Hydrogen.
3. Explain why the atomic radius of Oxygen is smaller than the atomic radius of Boron.
4. Explain why the atomic radius of Helium is smaller than the atomic radius of Neon.
5. In what region does a slight deviation exist for the rules discussed above? Why?
6. (# 59 from the text) Choose the larger atom from the following pairs:
A) Al or In
B) Si or N
C) P or Pb
D) C or F
7. (#61 from the text) Arrange the following elements in order of increasing atomic radius: Ca / Rb / S / Si / Ge / F
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Chem 31 SI 11/08/09
Periodic Properties
Trends in Ions and Ionization Energy
1. How does the atomic radius of a cation compare to its corresponding neutral atom and why? Circle the larger
species:
Li vs Li+.
Ca vs Ca2+.
2. How does the atomic radius of an anion compare to its corresponding neutral atom and why?
Circle the larger species: O vs O2-.
N vs. N3-
3. An isoelectronic series is a group of species with the same number of electrons. List the species in the following
isoelectronic series in order of decreasing atomic radius: F- / Ne / O2- / Mg2+ / Na+
4. On the periodic table above, use arrows to indicate the increase in first ionization energy vertically and
horizontally.
5. Why does Beryllium have a larger first ionization energy than Magnesium?
6. Why does Beryllium have a larger first ionization energy than Lithium?
7. Consider the image on the top right of the page. The x-axis is atomic number and the y-axis is first ionization
energy. The chart generally follows the trends already described; however, two dips occur between Li and Ne, and
again between Na and Ar. Account for both of these deviations / exceptions.
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Chem 31 SI 11/08/09
Periodic Properties
8. Which would you expect to require the highest amount of energy: the second ionization of sodium or the second
ionization of magnesium? Briefly explain why.
9. (#75 from text) For each of the following elements, predict where the “jump” occurs for successive ionization
energies:
A) Be
C) O
B) N
D) Li
10. What element has a higher first ionization energy than any other element on the periodic table?
A. Radon
B. Francium
C. Hydrogen
D. Helium
11. Which of the following statements is true regarding the second ionization energy?
A. The second ionization energy can be greater than or less than the first ionization energy depending on
the electron configuration.
B. The second ionization energy is always positive.
C. The second ionization energy can be positive or negative, depending on the electron configuration.
D. The second ionization energy for an ion with a noble-gas electron configuration is always less than the
second ionization energy for an ion with multiple valence electrons.
Trends in Electron Affinity and Metallic Character
1. On the above periodic table, use arrows to show the general direction of metallic character.
2. Although the trends are less consistent, outline the general trends for electron affinity. What exception exists for
the 5A elements and why?
3. (#77 from text): Choose the element with the more negative (more exothermic) electron affinity from each of the
following pairs:
A) Na or Rb
C) C or N
B) B or S
D) Li or F
4. (#81 from text): Arrange the following elements in order of increasing metallic character: Fr / Sb / In / S / Ba / Se
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