1. Modern Atomic Theory

2. Bohr Model
Shows location and number of protons, neutrons, and electrons
Protons and neutrons inside nucleus
Electrons outside nucleus

3. Electron Energy Levels
Electrons outside the nucleus are in energy levels
Each “shell” or level holds a certain number of electrons
The number of energy levels filled in an atom depends on how many electrons it has

4. Valence Electrons
Electrons in the outermost energy level are known as valence electrons
We will see how these valence electrons help determine the chemical properties of an atom (bonding, reactivity, etc.)

5. Atomic Models Build a Bohr model to represent your element.
Then, trade with another group and answer the following questions based on their model:
What is the element’s name?
How many protons, neutrons, and electrons does it have?
What is the atomic mass? Atomic number?
How many valence electrons does it have?
What is its overall charge?
Is this the most common isotope?

6. Lewis Dot Model
Shows the number of valence electrons

7. Practice
Pick three elements of your choice and draw the Lewis dot structure to represent them.