Download Baby-Quiz

Baby-Quiz
1. If all objects emit radiation, why don’t we see most of them in the
dark?
2. Suppose you were a nineteenth-century scientist who had just
discovered a new phenomenon known as Zeta rays. What experiment
could you perform to define if Zeta rays are charged particles or e/m
waves? Could this experiment distinguish between neutral particles
and an e/m wave?
3. If a metal surface is illuminated by light at a single frequency, why
don’t all the photoelectrons have the same kinetic energy when they
leave the metal’s surface?
4. What property of the emitted electrons depends on the intensity of
incident light?What property of the emitted photoelectrons depends
on the frequency of incident light?
1. What meaning do we give to the square of the matter-wave
amplitude?
2. An electron and proton have the same speeds. Which has
the longer wavelength? Why?
3. The wavelength of red light is 600 nm. An electron with a
speed of 1.2 km/s has the same wavelength. Will the
electron look red? Explain.
Particle in a Box
Where would you most likely find an electron
in the first excited state for a one-dimensional
box?
Quantum Mechanical View of
Atoms
The electron can be thought of as spread out in
space as a “cloud”.
Quantum Mechanics of the
Hydrogen Atom
n – principal quantum number, positive
integer;
l – orbital quantum number, is related to the
magnitude of the angular momentum of the
electron; at given n can take integer values
from 0 to (n-1);
ml – magnetic quantum number, is related to
the direction of the electron’s angular
momentum, and it can take an integer values
from –l to +l.
Zeeman Effect
Spin Quantum Number, ms
Conceptual Example: Possible
States for n=3
How many different states are possible for an electron whose
principal quantum number is n=3?
Selection Rule
Another prediction of quantum mechanics is that
when a photon is emitted or absorbed, transitions can
occur only between states with values of l that differ
by one unit.
The Exclusion Principle
No two electrons in an atom can occupy the
same quantum state.
Complex Atoms and Periodic
Table of Elements
1. How many electrons have the quantum numbers n=5 and
l=1?
2. How many electrons can have the quantum numbers n=5
and l=4?
3. Why do some minerals glow when they are illuminated
with ultraviolet light?