The Development of a New Atomic Model
Name:___________________
(Ch. 4 Sect. 1)
Problem: Rutherford's model of the _______ was an improvement but was incomplete. It did
not explain how the atom’s negatively charged __________________ are distributed around
the ____________ nucleus. What prevented electrons from _________ _________ into
the positive nucleus? Rutherford’s atoms should collapse! New studies revealed a relationship
between ____________ and an atom’s ________________.
>Light has characteristics of both _________________ and ____________.
The ________ Description of Light
Visible light is a kind of ___________________
radiation (a form of ___________ that has
__________________ behavior as it travels
through __________.
ELECTROMAGNETIC SPECTRUM
WAVELENGTH (λ) = distance between corresponding ___________ on adjacent waves
Units = _____, _____, or _____
FREQUENCY (υ) = number of waves that pass a given ____________ in a specific ________,
usually one second; Units = _______________ or _____
RELATIONSHIP:
c=λυ
>When certain frequencies of _________ strike a metal, electrons are
emitted.
a.k.a. the "photoelectric effect"
Scientists couldn't explain why the light had to be of a minimum ______________
in order for the photoelectric effect to occur.
The ________________ Description of Light
Max Planck (Germany, 1900) suggested that hot objects emit energy in small, specific
___________ of light called ________________. A "quantum" of energy is the minimum
_______________ of energy that can be __________ or gained by an atom.
Albert Einstein (Switzerland, 1905) expanded on Planck's theory by introducing the radical idea
that electromagnetic radiation has a dual “_________-______________” nature. Light can
travel with ______________ properties but also as a stream of ________________.
Photon = ______________ of electromagnetic radiation having ______ mass and
carrying a quantum of energy
>Electrons exist only in very specific _________ states for every ________
of each element.
When a ____________ is passed through a gas at low pressure, the potential energy of the
gas atoms _______________.
GROUND STATE = lowest _____________ state of an atom
EXCITED STATE = state in which an atom has higher potential ____________ than ground state
Atoms give off ___________, often in the form of colored light by falling from a
___________ energy level to a __________ energy level.
Discoveries:
-electrons can only be found at certain ____________ levels
-each energy level requires a certain amount of energy
-lower levels (___________ to nucleus) have lower energy
-higher levels (___________ from nucleus) have higher energy
EMISSION OF ENERGY BY ATOMS
Energy
ENERGY LEVELS OF HYDROGEN ATOMS
Hydrogen Emission Spectrum
Energy
Niels Bohr (Denmark, 1913) Physicist and student of _______________
Model: _______________ rungs
(circular _______________)
Problem: Bohr’s model works best for
___________________, but it is not complete
for other elements with more _________________.
QUANTUM MODEL OF THE ATOM (Ch. 4 Sect. 2)
Louis deBroglie (France, 1924) and Erwin Schrödinger (Austria, 1926)
Wave Equation:
Quantum Theory = mathematical description of the _______ properties of electrons and other
very small _______________
“Probability Map” of an ______________ location based on ________________ analysis
-->"ORBITALS" are nothing like ________