Transcript John Dalton Atomic Model

J.j. Thomson Atomic Model
• Plum Pudding Model or Blueberry
Muffin Model
• Proposed in 1904
• Negatively charged electrons (raisins
or blueberries) are surrounded by a
positively charged “pudding” (or
muffin)
Ernest Rutherford Gold Foil Experiment
• Discovery of the atomic nucleus
• Rutherford shot alpha particles at a piece of
gold foil surrounded by detectors
• This suggests that they hit something larger = Nucleus
• Gold Foil Video Demonstration
• Expected Outcome:
• Alpha particle shoots
straight through,
electrons according to the
Plum Pudding Model are
not enough to deflect the
particles
• Real Outcome:
• Alpha particles deflected
in some instances
• This suggests that they hit
something larger =
Nucleus
Ernest Rutherford Atomic Model
• Gold Foil experiment
marked the discovery that
the atom was made up of
mostly empty space and
contained a positively
charged nucleus
• Rutherford Model suggests
that atoms are unstable
Niels
Bohr
Atomic
Model
• Proposed in 1913
• Atoms are mostly empty space with
a positively charged nucleus
surrounded by electrons that travel
in circular orbits (like the solar
system)
• Revised Rutherford’s atom to create
a more stable model of the atom
Present Day Atomic Model
• James Chadwick discovered the
neutron in 1932
• The neutron is a subatomic particle
that resides in the nucleus and has
no charge
• This model says that we can’t
know the exact location of the
electron but the electrons are
more likely to be in specific areas
of the atom
• This cloud model shows the
possible locations of the electrons
at any moment