Download Development of the Atomic Model

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
A
B
C
Charge
Relative
Mass
Directions: Put the number of the definition from the list below into the square with the appropriate
term. Check your answers by adding the numbers to see if all the sums of all rows, both across and down add
up to the same number, the Magic #.
Democritus
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Dalton
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Thomson
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Chadwick
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Total
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Rutherford
Proton
Atom
Bohr
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Wave Model
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Neutron
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Nucleus
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Alpha particle
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Electron
Model
Energy levels
Electron cloud
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Total _____ _____
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2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
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Magic Number ______
Represented by a symbol; all are found on the Periodic Table
Made a mental model of the atom; Greek philosopher
Used by Rutherford in his experiment; made of two protons and two neutrons
The paths in which electrons circle the nucleus according to the Bohr model
The positive particle in the nucleus of an atom
The tiny positive core of an atom; contains protons and neutrons
Formed the atomic theory model of the atom; English schoolteacher
Discovered the nucleus using his gold foil experiment
Current explanation of where electrons might be found in the atom
Used by scientists to explain something we can not see or understand
The smallest particle of an element that has the properties of that element
Discovered the neutron
Current model of the atom; proposed by Schrodinger
Mass of protons and neutrons
Developed the model of the atom in which electrons orbit the nucleus in energy levels
The negative particle that circles the nucleus
The neutral particle in the nucleus of an atom
Proposed the “plum-pudding” model of the atom; discovered the electron