Quantum Model of the Atom
Objectives:
 Trace the development of the quantum model of the atom
Niels Bohr (1913)
Theory: ELECTRONS ARE PARTICLES
Planetary Model- Electrons are in orbit around the nucleus
 Electrons in orbit have fixed energy
 Electrons do not fall into the nucleus
Evidence for the Planetary Model- Atomic emission of hydrogen proved that there were
orbits of fixed energy and that electrons could gain energy and reach a new energy
level. When the electron lost the energy, the wavelength of light emitted confirmed
the scientists’ calculations that the energy of the light absorbed is equal to the
difference between the energies of the orbits.
Werner Karl Heisenberg (1927)
Theory: THE PARTICLE BEHAVIOR OF ELECTRONS IS NOT SUPPORTED
Heisenberg Uncertainty Principle-it is not possible to mathematically
determine the position and velocity of electrons. This means that
orbiting is impossible!
Erwin Schrödinger (1926)
Theory: ELECTRONS ARE POINTS, BUT THEIR REPULSIVE FORCES CAUSE THEM
TO BEHAVE LIKE WAVES
 Quantum Mechanical Model- Describes the probability of
finding an electron in a certain volume of space
surrounding the nucleus is in a fuzzy cloud
electron cloud- region in space where there exists a 90% probability of
finding an electron
Orbital
Why is the Bohr Model of the atom incomplete?
T. O’Toole
Minute Paper
-Describe the Bohr Model?
Electrons orbit the nucleus at fixed energy without being drawn into the
nucleus
-Why does the Bohr Model work for hydrogen but not for other atoms?
Hydrogen has only 1 electron. All other atoms have more electrons which
will repel one another and force the energy of the orbit to change.
How do I get from where I am to where I’m going?
The 10 Minute Makeover
Customize your learning by choosing from the following options each
night
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Complete the appropriate section on the Portfolio Page
Complete SYS Assignment related book work
Review the PPT file on the website
Read pages 361-364 in the book
Practice using: http://www.quia.com/cz/122691.html
Check out the tutorial resources in the LiveBinder like this video about the Quantum
Model that replaces Rutherford’s model
https://www.youtube.com/watch?v=45KGS1Ro-sc
Review the skills from today’s Train Your Brain
Why is the Bohr Model of the atom incomplete?
T. O’Toole