LAST NAME_________________ FIRST NAME_______________ DATE___________ PERIOD____
Development of the Atomic Model
In each box below, state the name of the scientist/philosopher responsible: Dalton, Democritus, Thompson,
Rutherford, Bohr, Thomson
There are small, negatively charged
particles inside an atom.
There is a small, dense, positively
charged nucleus.
Most of an atom’s mass is in the
nucleus.
Electrons are located in orbits.
He conducted the cathode ray tube.
Atoms contain mostly empty space.
Atoms are small, hard particles
He conducted experiments
combining elements to illustrate
how they combined.
First to State that “Atoms are
Indestructible.”
Electrons travel in definite paths
like the orbit of the Moon around
Earth
His theory of Atomic Structure led
to the “plum-pudding” model.
He determined the electrical charge
of an electron.
Atoms are constantly moving.
He conducted the Gold Foil
Experiment
Elements combine in specific
Proportions
He determined the mass of an
electron.
Atoms of the same element are
identical.
To the right are
illustrations of two
scientist’s concept of the
atoms. Label the electrons
in both illustrations with a
negative (-) sign and the
nucleus in the illustration
to the right with at positive
sign (+). Identify which
illustration was believed to
be correct before (and after) Rutherford’s gold-fil experiment.
In the boxes provided below describe the locations of the subatomic
particles in the labeled model of an atom of nitrogen, and give the
charge and relative mass of each particle.
Location
Charge
Relative
Mass
A
B
C
