Name
Class
Date
Skills Worksheet
Reinforcement
Atomic Timeline
If you were asked to draw the structure of an atom, what would you draw?
Throughout history scientists have accepted five atomic models. Our perception of
the atom has changed from the early Greek model because of clues or evidences
that have been gathered through scientific experiments. As more evidence was
gathered old models were discarded or improved upon. Your goal is to trace the
atomic theory through history.
You and your partner will use the sources provided (textbook and internet) to develop
a timeline that outlines the key scientists and experiments associated with the
development of modern atomic theory. The timeline should include the names of the
scientists, a description of the accomplishments, pictures of experimental equipment
or atomic models, and description.
The table below contains a number of statements connected to major discoveries in
the development of atomic theory. These must be included in your timeline
1. In each box, write the name of the scientist(s) associated with the statement.
Choose from among the following scientists: Democritus, Rutherford, Thomson,
Dalton, Bohr, Schrödinger, and Heisenberg.
2. On a separate sheet of paper, construct a timeline, and label the following: 440
BCE, 1803, 1897, 1909–1911, 1913, and the twentieth century. Cut out the boxes
and tape or glue each box at the correct point along the timeline.
A. Most of an atom’s mass is in the
nucleus.
B. There is a small, dense, positively
charged nucleus.
C. There are small, negatively charged
particles inside an atom.
D. Electrons can jump from a path in
one level to a path in another level.
E. Atoms of different elements are
different.
F. He conducted the cathode-ray tube
experiment.
G. Atoms are small, hard particles.
H. Atoms contain mostly empty space.
I. Atoms are “uncuttable.”
J. He conducted experiments in
combining elements.
K. Electrons travel in certain paths, or
energy levels.
L. Electron paths cannot be predicted.
M. His theory of atomic structure led to
the “plum-pudding” model.
N. His model had electrons
surrounding the nucleus at a
distance.
O. Atoms of the same element are
exactly alike.
P. Electrons are found in electron
clouds, not paths.
Q. All substances are made of atoms.
R. Atoms are made of a single
material formed into different
shapes and sizes.
S. He conducted the gold foil
experiment.
T. He wanted to know why elements
combine in specific proportions.
3. Now find additional 5 facts (total should be minimum of 25) to add to the ones
given. These 5 facts must be from scientists that are NOT already named.
Your timeline should be on a poster paper (will be provided) with pictures and be
legible! This assignment will count as a test grade, so take your time and do a good
job! You will be given 2 days in the computer lab to research material and print
needed pictures. You will then be given 2 additional days in the classroom to put the
timeline together.
DUE DATE: ____________________
(Cut off rubric and hand in with completed timeline)
----------------------------------------------------------------------------------------------------------------Names: ____________________________
Class: ___________
____________________________
Atomic Structure Timeline Rubric
Timeline Poster/Pamphlet
25 Fact Entries
50 pts _______
10 Required Scientist
20 pts _______
Pictures (min. of 5)
10 pts _______
Grammar & Spelling
5 pts
_______
Creativity/Neatness
5pts
_______
Total:
90 pts _______