1. Starter
Which of the following correctly compares the relative sizes of subatomic particles to the relative sizes of animals? Explain your reasoning for your choice.
If a proton is the size a blue whale a neutron would be another blue whale and the electron would be a tick. 
If a proton is the size of a horse, then the neutron would be an elephant, and the electron would be a fly. 
If a proton is the size of a dog, then the neutron would be like a cat, and an electron would be a mouse. 

2. Bohr Models
Atomic Structure

3. Objective
I can generalize the relationship of proton number to the elements identity.

4. Atomic weight or Mass in amu
Elements
Atomic #
Element symbol
Atomic weight or Mass in amu
Element name

5. Isotopes
The number of neutrons can vary.
Isotopes: atoms of the same element that have the same number of protons but a different number of neutrons

6. Writing Isotopes
Isotopes can be written two ways: 1. 2.

7. Finding the Number of Neutrons
number of neutrons = mass number – atomic number

8. The Bohr Model
Bohr proposed that an electron is found only in specific circular paths, or orbitals, around the nucleus.
Each electron has a fixed energy.
Energy levels: the fixed energies an electron can have

9. Bohr Diagrams
Each shell or energy level can only hold a certain amount of electrons.
1st shell = 2 electrons
2nd shell = 8 electrons
3rd shell = 18 electrons
Quantum: the amount of energy required to move an electron from one energy level to another energy level.

10. Steps to drawing Bohr Diagrams
Determine the number of electrons in your element 1
Draw a nucleus with the element symbol inside 2
Draw the shells around the nucleus 3
Add the electrons 4
Steps to drawing Bohr Diagrams

11. How many electrons Find your element on the periodic table.
Determine the number of electrons.
A neutral atom has the same amount of protons and electrons
The Atomic number is the number of protons in an atom
This is how many electrons you will draw.

12. Electron Configuration

13. Electron Configuration

14. Electron Configuration

15. Electron Configuration

16. Electron Configuration

17. Electron Configuration

18. Can you see any patterns?

19. Pattern 1: Energy Levels
Period: the rows of a periodic table
Elements in the 1st period have one energy level.
Elements in the 2nd period have two energy levels, and so on.

20. Pattern 2: Valence Electrons
Each of the elements in the first column that have one electron in their outside shells.
Valence Electron: electrons found in the energy level furthest from the nucleus