Download Rutherford Model of the Atom Objective

Rutherford Model of the Atom
Objective
chapter 14
lesson 3
you will be able to explain qualitatively the
significance of Rutherford’s discovery
Gold Foil Experiment
Rutherford was attempting to lend support to Thomsonʼs
atomic model by sending a beam of massive alpha
particles at a sheet of very thin (approximately 400
atoms thick) gold foil.
Rutherford
Results:
Most of the particles went
Some deflected at
stated, “It
was as if
you fired a
shell at
tissue
paper and it
came back
and hit
you.”
A study of the paths of the alpha particles revealed that
they were curved rather than sharp.
This lead him to believe that there was a large positive
charge repelling the positively charged alpha particles.
He said that it must be in the center of the atom and he
called it the nucleus.
How are the atoms held together?
A charged particle in an electric field will have electric
potential energy as follows.
Work = Force x distance=∆E
Example: Determine the potential energy of an alpha
particle when it is 1.0 x 10-10 m from the gold nucleus.
This model was not well received!
Assignment
Read p. 766-770
Do practice problems #1,2 p. 769
and
check and reflect p.770 # 1-4