1. Bohr Model to Represent Electrons

2. Electron Review
Electrons orbit the nucleus in the space called the “cloud”.
They have a -1 charge
Atomic mass = 1/1836 (so tiny, we don’t even count it!)
Electrons are located in energy levels around the nucleus
This is just how far away from the nucleus an electron is

3. Niels Bohr’s model of the atom focused on the description of the electrons in an atom

4. Different atoms have different numbers of orbitals, which determines how many electrons each atom can have
 1 orbital
 2 orbitals
 3 orbitals
 4 orbitals
 5 orbitals
 6 orbitals
 7 orbitals
 6 orbitals
 7 orbitals

5. How many orbitals do the following atoms have?Zr C Au H Pa

6. Each orbital can hold a specific amount of electrons:
1st energy level: up to 2 e-
2nd energy level: up to 8 e-
3rd energy level: up to 8 e-
4th energy level: up to 18 e-
Valence Electrons: number of electrons in the outermost energy level
Core Electrons: All electrons minus the valence electrons

7. Which energy level has the highest energy?
The father away the electrons are from the nucleus, the more energy an atom has.
For example, elements with 5 orbitals have more energy than elements with 2 orbitals.
Which energy level has the highest energy?
1 or 5
7 or 2
3 or 4

8. Brain Break: Balloon Bounce

9. Rules for Filling Electron Orbitals:
Always start at the level closest to the nucleus
Each level MUST be full before you can move to the next. C
P = 6
N = 6

10. How to draw Bohr Models:
Determine the number of protons, neutrons and electrons that an atom has.
Start at the level closest to the nucleus and add 2 electrons. C
P = 6
N = 6

11. If more than 2 electrons, move to the next energy level and continue to fill in electrons.
Remember: this level gets 8.
Continue to fill in energy levels until there are no more electrons.
Look at the electrons in the outermost energy level, these are the valence electrons.
The core electrons are all the electrons in the inside of the electron cloud. C
P = 6
N = 6

12. Double Check: does your number of orbitals drawn equal the number of orbitals that it should have from the periodic table? C
P = 6
N = 6

13. Example:
Draw the Bohr Model for the following atom then fill in the subatomic particles. N
#p: #n: #e-:
#valence electrons: #core electrons:
Energy level the valence electrons are in:

14. Example:
Draw the Bohr Model for the following atom then fill in the information about that atom. Br
#p: #n: #e-:
#valence electrons: #core electrons:
Energy level the valence electrons are in:

15. Example:
Draw the Bohr Model for the following atom then fill in the information about that atom. Xe
#p: #n: #e-:
#valence electrons: #core electrons:
Energy level the valence electrons are in: