Atomic Timeline Project s1

Name: ______Hour: ______

Atomic Timeline Project Chemistry A

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. It has been through new discoveries by philosophers and scientists in chemistry, as well as physics, that the model of the atom has expanded and changed over time. 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 to key dates, their contributions to the atomic model and a visual representation of their contribution. 2. Be chronological in its sequence, with the dates clearly shown (it need not be to scale), and at a minimum include the information contained below. 3. Be neat and legible. 4. Be larger than 8.5 x 11 inch size but no larger than half of a posterboard. This could involve 2 sheets (or more) of typing paper posted on cardboard, for example. I highly recommend posting any type of typing paper on cardboard for support!

Deadlines and Guidelines: • Your timeline is due on ______. All procedures for late work are to be followed for this project. • You are welcome to work (but NOT copy) together in gathering your information, but your timelines are to be completed independently of one another! • You do not have to follow the typical horizontal timeline format; you may be creative and use any format you wish.

Extra Credit: • Extra credit may be given for the inclusion of other atomic scientists and/or philosophers as well as for creativity. Additional scientists that may be included are Wilhelm Roentgen (1895), Henri Becquerel (1896) and Marie & Pierre Curie (1898)  All required information for the original group of atomic scientists and/or philosophers should be included. A maximum of 5 additional scientists may be included for extra credit. Extra credit points will be awarded at my discretion and will be based on content.

Recommended Sources: Your textbook is probably the best source of information for this project. Often the descriptions are easier to understand that 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 WAAY more complicated than you need. Try searching “atomic timeline” from a search engine like Google. Part 1: Scientists/Philosophers with Dates

Henry Moseley (1914) John Dalton (1803)

Dimitri Mendeleev (1869) JJ Thomson (1898)

Robert Millikan (1909) Democritus (460-370 BC)

James Chadwick (1932) Niels Bohr (1922)

Ernest Rutherford (1911) Erwin Schroedinger (1926)

Werner Heisenberg (1927)

Part 2: Descriptions of Contributions

Developed the Quantum Mechanical Model of the atom, which treats electrons like waves. Improved upon the Bohr Diagram of the atom with his Electron Cloud Model.

Identified the neutron, the final subatomic particle. He concluded that the nucleus is made of both protons and neutrons.

Developed modern atomic theory: matter is composed of atoms, atoms are identical in size, mass etc, atoms cannot be created, divided or destroyed, 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 “atom”. Developed the Heisenberg 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.

Determined the charge and mass of an electron using the Oil Drop Experiment.

Proposed that the lowest allowable energy state of an atom is called its ground state and when an atom gains energy it is said to be in an excited state. Suggested that electrons move around the nucleus in shells, which relate to the energy level of the electron.

Organized the elements into the first periodic table, which was based on the mass of each element.

Part 3: Visual Representations of Contributions ------

Name: ______Hour: ______

Atomic Timeline Grading Rubric ** Cut this half of the paper off and attach to your timeline when you turn it in** r s r v n n n y k g d u a r e o o e h c r e i l t t s g o k e o e i l i l e w n f l b B r a m i s l e r d i n c o o d d D a e e o h o n M h h s M r i m e T t C h e e u M c H D R S

Points:

Date in Order /11

Correct /22 Description

Correct /11 Diagram

Neat/Legible /6

Extra Credit

Total: /50