Name ___________________________________ Date ______________________ Class ______________________
Chapter 4 – Atomic Structure
Atomic Timeline Project
Purpose: To help you piece together the story of what we know about the “atom”, you will be creating a timeline
depicting the development of the scientific model of the atom. Your assignment is to research the major contributors
and significant discoveries that have impacted the atomic model and, from this material, develop a timeline.
Requirements:
Your timeline MUST:
1. Match each of the 11 scientists and/or philosophers located below with the information describing their work AND
with the best picture that best represents their work.
2. Be in chronological order with the dates clearly shown.
3. Be neat and legible.
4. Have color included somehow to add creativity.
5. Be turned in with the rubric attached (stapled) to the poster.
Recommended Sources:
Your textbook is probably the best source of information for this project. Often the descriptions are easier to
understand than what you might find on a website. Also, dates may vary on different websites.
If you choose to use a website, I would find one that is not waaay more complicated than you need. Try searching
“atomic timeline” from a search engine like Google.
---------------------------------------------------------------------------------------------------------------------------------------------------------------Atomic Timeline Grading Rubric
**Cut this portion of the paper off and attach to your timeline when you turn it in**
Date in
order
Correct
Description
Correct
Diagram
Heisenberg
Mendeleev
Thomson
Period: ______________
Rutherford
Millikan
Dalton
Chadwick
Bohr
Schrodinger
Democritus
Moseley
Name: _______________________________________________
Points
/3
/11
/11
Neat/Legible
/3
Added Color
/2
TOTAL:
/30
Part 1: Scientists/Philosophers with Dates
Henry Moseley (1914)
John Dalton (1803)
Dmitri Mendeleev (1869)
JJ Thomson (1898)
Robert Millikan (1909)
Democritus (460-370 BC)
James Chadwick (1932)
Niels Bohr (1922)
Ernest Rutherford (1911)
Erwin Schrödinger (1926)
Werner Heisenberg (1927)
Part 2: Descriptions of Contributions
Improved upon the Bohr Diagram of the atom with his Electron Cloud Model which stated that electrons are found in a
more general “cloud” like area around the nucleus rather than in tight rings.
Identified the neutron, the final subatomic particle. He concluded that the nucleus is made of both protons and
neutrons.
Developed the modern atomic theory: matter is composed of atoms, atoms are identical in size, mass etc, atoms cannot
be created, divided or destroyed, and atoms combine into compounds and in chemical reactions atoms are separated,
combined or rearranged.
Proposed the nuclear atomic model with a centrally located, positively charged nucleus based on the result of his Gold
Foil Experiment.
Discovered that atoms of each element contain a unique number of protons, referred to as the element’s atomic
number. Reorganized the periodic table to create what we use today.
First person to propose that matter was not infinitely divisible. First person to use the Latin term “atomos”, which
means atoms.
Developed the Uncertainty Principle, which states that the exact position or location of an electron in an atom cannot be
predicted.
Identified the electron (first subatomic particle) using cathode ray tubes. Proposed the plum pudding (chocolate chip
cookie) model of the atom.
Determine the charge and mass of an electron using the Oil Drop Experiment.
Suggested that electrons move around the nucleus in very specific shells or rings which relate to the energy level of the
electron. Created a diagram named for him that we still use today.
Organized the elements into the first periodic table, which was based on the mass of each element. This is not the exact
same table that we use today.
Part 3: Visual Representations of Contributions