Untitled - Kelly Walsh High School

116 CHEMISTRY FOR THE UTTERLY CONFUSED
Quick Tip
Some students mistakenly list the units of Planck’s constant as J/s. You should
be careful not to be one of these students.
When beginning a problem of this type you should, as always, carefully extract
the values (including units) from the question. You should then label each of
the extracted values with the appropriate symbol from the equation set. To help
in the assignment, pay attention to the units. The energy, E, will have units of J
or kJ. The frequency, , will have units of 1/s s 1 Hz. The wavelength, ,
will always have units of length, usually m or nm, but also English units or Å.
Mass, m, may have any mass unit, and you will need to change this mass to kilograms.
Velocity, v, may have any units of distance (length) divided by any unit
of time. In most cases, you will need to convert the velocity to m/s.
Once you have extracted and labeled the values in the problem (including the
value being sought), you finish the problem by matching the symbols you have
with the given equations. After rearranging the equation, if necessary, you will
enter the appropriate values and conversions to get the final answer.
In this chapter, you learned about the electronic structure of the atom in terms
of the older Bohr model and the newer quantum mechanical model. You learned
about the wave properties of matter, and how to describe each individual electron
in terms of its four quantum numbers. You then learned how to write the
electron configuration of an atom and some exceptions to the general rules.
1. Write the equation that relates energy to frequency.
2. How many different ground states may an atom have?
3. What are the maximum number of electrons that may occupy s-, p-, d-, and
f-, orbitals?
4. List the four quantum numbers and give their symbols.
5. State Hund’s rule.
6. Give the full electron configuration of each of the following.
a.F b.Cu c.Re
7. A laser emits light with a wavelength of 645 nm. What is the frequency of this
light?
8. An alpha particle (mass 6.6 10 24 g) emitted by radium travels at 5.5
10 10 m/h. What is its de Broglie wavelength (in meters)?
9. It requires 239 kJ/mol to separate the chlorine atoms in a Cl 2 molecule. What
wavelength of light would be necessary to separate the atoms in a single
chlorine molecule?