Links/Connections
Within Chemistry

The outer-shell electron configuration of an atom determines the chemical behavior,
physical behavior, and bonding of that element. Therefore this topic is the perfect
lead-in for Periodicity or Chemical Bonding.
Before students can understand topics in Nuclear Chemistry they must know about
the structure of the atom. So this topic unit is an important precursor.

BETWEEN
CHEMISTRY
AND OTHER
DISCIPLINES

Chemists make use of our knowledge at the atomic and molecular level to explain and
predict the behavior of macroscopic materials. Some areas of physics concentrate on
expanding knowledge at the sub-atomic level. Atomic structure is an area where
chemistry and physics have a large overlap. Your school’s physics teacher may have
much of the laboratory and demonstration equipment needed for this topic.
Because an atom is a very small particle, it cannot be seen with the naked eye. Yet
electron microscopes that can produce magnification factors in the millions have
allowed scientists to photograph images of individual atoms. The first motion
pictures of the movement of single uranium atoms was achieved in 1976 by physicists
at the University of Chicago. What did an atom of uranium look like? The individual
uranium atoms appeared as roundish spots with bright edges and dark centers.
Physicists continue to expand our notion of atomic structure by continually discovering
new subatomic particles. Many are now known, e.g., pions, muons, quarks, etc. How
many more might yet be discovered when more powerful atom smashers are built?
How might the super-collider presently being built in Texas help us to understand
the atom better? (Idea contributed by Angie Matamoros.)

TO THE
CONTEMPORARY
WORLD

Television tubes are merely sophisticated cathode ray tubes. The electron stream
from the rear of the tube is aimed at the front surface, which is coated with materials
(called phosphors) that have readily excitable valence electrons. These electrons are
temporarily energized. When they return to lower-energy states, the energy is
released in the form of visible light with distinctive colors. Three major groups of
phosphors (phosphorescent dots) in red, green, and blue arrays constitute one form
of a color TV tube.
The details of atomic structure are particularly important in such medical applications
as CAT, MRI, etc.