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Atomic theory
Challenge Problems
1. a. Write the ground state electron configuration for a phosphorus atom.
b. Give the quantum numbers for each of the valence electrons in a
single phosphorus atom when it is in its ground state.
c. Is an isolated phosphorus atom in its ground state paramagnetic or
diamagnetic? Explain.
d. Explain how the electron configuration of the phosphorus atom in the
ground state consistent with the existence of the following
compounds: Na3P, PCl3 and PCl5.
2. Three series of lines can be found in the Hydrogen atom. They include
the ultraviolet (Lyman), the visible (Balmer), and the infrared (Paschen).
a. Explain why the emission spectrum consists of several discrete lines
and not a continuous spectrum.
b. What quantity causes a line to be included in a particular series?
What quantity distinguishes one series from another?
c. Draw an energy level diagram for Hydrogen. On your diagram
include the transition for the largest wavelength in the Balmer series.
Explain why you chose this line.
d. Explain the difference between an absorption spectrum and an
emission spectrum. Explain why the absorption spectrum of
Hydrogen at room temperature includes only the Lyman series.
3. Use periodic trends and modern atomic theory to explain each of the
following:
a. As the atomic number within a family increases, the atomic radius
increases.
b. The radius of the sodium ion is smaller than the radius of the sodium
atom.
c. The radius of an oxygen ion is larger than the radius of a fluoride ion.
d. The ionization energy of fluorine is greater than lithium.