1. Atomic Model
Unit 3.1

2. Atoms
Atom: Smallest piece of matter that has the properties of the element.
Nucleus: Dense, heavy center of an atom.
Protons: particles with a positive charge
Neutrons: particles with neutral (no) charge
Electron cloud: Low-density, outer region of an atom.
Electrons: particles with a negative charge and virtually no mass.

3. % of an atom is nothing
Average radius of an atomic nucleus is 1/10,000 of the atom’s size.
If a nucleus is the size of a pea in the center of a football stadium, then small flies flying at the outer part of the stadium would be the electrons. There wouldn’t be anything between the nucleus and the electrons.

4. (Round to 12)
6P + 6N = 12

5. Bohr
Model-a visual representation of something to help us understand what it looks like
Bohr Model-electrons travel in a fixed orbit around the nucleus
Each orbit, or orbital, is called an energy level

6. How do you Determine the # of Protons, Neutrons, and Electrons?
Let’s Do Boron as an example…
Atomic Number: The number of protons (5) AND electrons (5)
Average Atomic Mass: The number of protons and neutrons (because electrons are so small, their mass isn’t factored in)
Round up!
To calculate:
Atomic Mass – Atomic number = # of neutrons
11- 5 = 6

7. Draw This…

8. How Many Electrons are in Each Energy Level?
1st Level: Maximum of 2 electrons
2nd Level: Maximum of 8 electrons
3rd Level: Maximum of 8 electrons