1. Atoms and Atomic Theory
Essential Questions: How and why has the Atomic Theory changed over time? Why do we use models in science?

2. DO NOW 1. Open your notebook to a new page, write today’s date.
2. THINK ABOUT IT: If atoms are so tiny that we can’t see them, how do we know what they look like?

3. Review of Atoms
Matter is anything that takes up space and has mass. All matter is made of atoms.
Atoms are the basic building blocks of matter. They make up everything around us; Your desk, the board, your body, everything is made of atoms!
Atoms are too small to see without powerful microscopes.

4. Models
Models are often used for things that are too small or too large to be observed or that are too difficult to be understood in a simple manner
In the case of atoms, scientists use large models to explain something that is very small

5. Atomic Theory Timeline
Scientist
Information
Model
Democritus
430 BC
Matter is formed of small pieces called “atomos” that cannot be broken down into smaller parts

6. Atomic Theory Timeline
Scientist
Information
Model
John Dalton
1808
All matter is made of atoms. Atoms are too small to see, indivisible and indestructible. All atoms of a given element are identical.

7. Atomic Theory Timeline
Scientist
Information
Model
J.J Thompson
1897
Atoms are made mostly out of (+) charged material, like a ball of dough. The (-) electrons are found inside the (+) material.

8. Atomic Theory Timeline
Scientist
Information
Model
Ernest Rutherford
1911
Discovered the nucleus of an atom and named the positive particles in the nucleus “protons”. Concluded that atoms are mostly empty space.

9. Atomic Theory Timeline
Scientist
Information
Model
Neils Bohr
1913
Proposed that electrons move around the nucleus in specific layers or shells.

10. Atomic Theory Timeline
Scientist
Information
Model
James Chadwick
1932
Discovered that neutrons were also located in the nucleus of an atoms and that they contain no charge.
Neutrons

11. Scientist Information Model
(Many Scientists!)
The Modern Atomic Theory
Electrons do not orbit the nucleus in neat planet-like orbits but move at high speeds in an electron cloud around the nucleus.

12.
Additional video resource:

13. Atoms and Atomic Theory
Essential Questions: How and why has the Atomic Theory changed over time? Why do we use models in science?

14. Atomic Structure: Day 2
DO NOW:
1. Take out your notes from yesterday
2. Think About It: Yesterday you learned about the history of the current model for atomic structure.
Why do we use a model of the atom in science? Has the model changed over time?
You should write down your thoughts and be ready to share….you do not need to copy the question.

15. Classwork
Today you will create a foldable summarizing the history of the atomic theory.
Objective: Explain why the atomic model has changed over time.
You will need:
Your notes from yesterday
Scissors
Glue
After you have completed your foldable and cleaned up you may go on to the follow-up question:
Question: In your own words, explain why the atomic theory has changed over time.