1. Atomic Structure
Objective: Describe the general structure of the atom, and explain how the properties of the first 20 elements in the Periodic Table are related to their atomic structures

2. Brainstorm What is matter? What is mass? What is an atom?
Give at least three examples. Give two examples of things that are NOT matter, (Hint: thoughts).
What is mass?
What is an atom?
Give at least three examples of things in this room that are made of atoms.
Is the air we breathe made of atoms? Explain your answer.
What is a scientific theory?

3. The Basics Matter: Anything that takes up space and has a mass.
Examples: a desk, a person, oxygen
Non Examples: feelings, thoughts
Mass: A measure of how much matter an object contains. Mass is related to weight.
Element: A substance that can not be broken down into a more simple substance.
Example: Gold, Oxygen, Carbon, Helium, Iron

4. The Basics Compound: A substance made of two or more elements.
Example: CO2 , H2O
Theory: A tested explanation with supporting evidence. Can be changed, revised or disproved.
Example: Theory of Evolution-The change in physical traits in a population over long periods of time.

5. Discussion Can scientist be proven wrong?
Can science theories be changed?
Is science a process that is continually worked on or is it set in stone?
Do many people usually contribute science knowledge?

6. Activity

7. Discovering the Atom Aristotle: Greek Philosopher 322 BC-384BC
Believed that four elements made up all things

8. Discovering the Atom: Dalton’s Contribution
John Dalton
England 1776
Science Teacher
Atom looked like a ball
Theory: All matter is made up of individual particles called atoms, which cannot be divided.

9. Discovering the Atom: J.J. Thomas
1800
Discovered the electron
Plum pudding model

10. Discovering the Atom: Ernest Rutherford
1900 New Zealand
Discovered protons and nucleus
Electrons move randomly in space

11. Discovering the Atom: Niels Bohr
1913
Electrons move in fixed orbit around nucleus

12. Discovering the Atom: Schrodinger and Chadwick
Erwin Schrodinger:
1926
Describes motions of electrons
Leads to electron cloud theory
James Chadwick
1932
Confirms the existence of neutrons
Nucleus contains neutrons and protons

13. The Atom – “Uncut” or “Indivisible”
The smallest part or unit of an element.
Cannot be broken down without losing its properties
Basic building block of matter
Makes up all physical things

14. Parts of the Atom Protons Positively charged sub-atomic particle
Found in the nucleus
Neutrons
Neutrally or no charge
Subatomic particle found in the nucleus
Electrons
Negative charge
Subatomic particle found outside of nucleus
Nucleus
Dense center of the atom
Positive charge

15. Atomic Number The number of protons for any given element
All element of one kind have the same number of protons
Example: All Hydrogen (H) atoms have just one proton
Atoms of different elements have different number of protons
Atomic number also gives us the number of electrons

16. Discuss What charge are protons? What charge are electrons?
Why do you think atoms have the same number of protons and electrons?

17. Neutral Atoms The positive protons and negative neutrons balance out.
This make the charge of an atom neutral or zero.
Draw an Example

18. Mass Number The number of protons and neutrons found in the nucleus
Protons + Neutrons = Mass Number
Example: Carbon has a mass number of 12
This means there are 6 protons and 6 neutrons
*Do the math

19. Practice Calculating the Number of Neutrons

20. Periodic Table

21. Bohr Model Looks like the solar system
Contains different energy levels
General Example:

22. Energy Levels and Orbitals
Each ring of the Bohr Model is an energy level
As you go further out from the nucleus the energy of the electron becomes greater
Electrons orbit around the nucleus much like the earth orbits around the sun

23. Electron Configuration
Configuration = Arrangement
Desks in the classroom are arranged in a specific way
Electrons are found in orbits around the nucleus. This is their “electron configuration”

24. Energy Levels and Orbits
Can contain only two electrons
Energy levels 2 and 3
Can contain up to eight electrons
Energy levels must be filled before electrons can move to the next shell
*Draw example labeling energy levels