 # Bohr Models are NOT Boring!

## Presentation on theme: "Bohr Models are NOT Boring!"— Presentation transcript:

Bohr Models are NOT Boring!
How to Draw Bohr Diagrams

Bohr Diagrams Find the element on the periodic table.
Determine the number of electrons--it is the same as the atomic number. This is how many electrons you will draw.

Bohr Diagrams Find out which period (row) your element is in.
1 2 3 4 5 6 7 Elements in the 1st period have one energy level. Elements in the 2nd period have two energy levels, and so on.

Bohr Diagrams C Draw a nucleus with the element symbol inside.
Write the number of Protons and Neutrons the element has inside the nucleus. Put a + by the P and a little 0 by the N. C P+ = 6 N0 = 6 Note: Round mass to nearest 1 when figuring neutrons.

The electron shells surrounding the nucleus each hold a particular number of electrons.
Shells are named with letters: 1 = K shell = 2 electrons 2 = L shell = 8 electrons 3 = M shell = 8 electrons 4 = N shell = 18 electrons 5-7 = O, P, Q = up to 32 electrons Remember: The outer shell of an atom (no matter what letter) can only hold 8 electrons!

Bohr Diagrams Carbon is in the 2nd period, so it has two energy levels, or shells. Draw the shells around the nucleus. C P+ = 6 N0 = 6

Bohr Diagrams C Add the electrons. Carbon has 6 electrons.
The first shell can only hold 2 electrons. Write the number of electrons that shell holds and e- for electrons an their charge. How many electrons are in the outer shell? C P+ = 6 N0 = 6 2 e-

Bohr Diagrams Since you have 2 electrons in the first shell, you need to add 4 more. C P+ = 6 N0 = 6 These go in the 2nd shell. Again, write e- and the number of electrons. 2e- 4e-

Bohr Diagrams C Check your work.
You should have 6 total electrons for Carbon. Only two electrons can fit in the 1st shell. The 2nd shell can hold up to 8 electrons. The 3rd shell can hold 18, but the elements in the first few periods only use 8 electrons. We’ll talk about how they fill tomorrow. C P+ = 6 N0 = 6 2e- 4e-

Bohr Diagrams Try Hydrogen: Atomic Mass: Atomic Number: Protons: Electrons: Neutrons: Shells: Valence electrons: H P+ = N0 =

Bohr Diagrams Check Yourself. H P+= 1 N0= 0 1e-

Bohr Diagrams Try Helium: Atomic Mass: Atomic Number: Protons: Electrons: Neutrons: Shells: Valence electrons: Try Helium He P+= N0=

Bohr Diagrams He P+= 2 N0= 2 Check Yourself! 2e-

Bohr Diagrams Try Oxygen: Atomic Mass: Atomic Number: Protons: Electrons: Neutrons: Shells: Valence electrons: O P+= N0=

Bohr Diagrams Check Yourslef! O P+= 8 N0= 8 2e- 6e-

Bohr Diagrams Try Aluminum: Atomic Mass: Atomic Number: Protons: Electrons: Neutrons: Shells: Valence electrons: Al P+= N0=

Bohr Diagrams Check Yourself! Al P+= 13 N0= 14 2e- 8e- 3e-

Bohr Diagrams Try Potassium: Atomic Mass: Atomic Number: Protons: Electrons: Neutrons: Shells: Valence electrons: K P+= N0=

Bohr Diagrams Check yourself! K P+= 19 N0= 20 2e- 8e- 8e- 1e-

You should know how to draw a Bohr Diagram for the first 20 elements.
Bohr Diagrams You should know how to draw a Bohr Diagram for the first 20 elements.

Periodic Table Study Guide
How to Draw Lewis Structures By Mrs. Hunt and Mrs. LaRosa 2008

Lewis Structures Find the element on the periodic table.
Determine the number of valence electrons. This is how many electrons you will draw.

Lewis Structures Find out which group (column) your element is in.
This will tell you the number of valence electrons your element has. You will only draw the valence electrons.

Groups - Review Group 8 = 8 electrons Group 1 = 1 electron
Except for He, it has 2 electrons Group 1 = 1 electron Group 2 = 2 electrons Each column is called a “group” 3, 4, 5, 6, 7 Each element in a group has the same number of electrons in their outer orbital, also known as “shells”. The electrons in the outer shell are called “valence electrons.”

C Lewis Structures Write the element symbol.
Carbon is in the 4th group, so it has 4 valence electrons. Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol. C

C Lewis Structures Check your work.
Using your periodic table, check that Carbon is in the 4th group. You should have 4 total electrons, or dots, drawn in for Carbon. C

C Lewis Structures On your worksheet, try these elements on your own:
P Ca Ar Cl Al C

H Lewis Structures On your worksheet, try these elements on your own:
P Ca Ar Cl Al H

P Lewis Structures On your worksheet, try these elements on your own:
Ca Ar Cl Al P

Ca Lewis Structures On your worksheet, try these elements on your own:
P Ca Ar Cl Al Ca

Ar Lewis Structures On your worksheet, try these elements on your own:
P Ca Ar Cl Al Ar

Cl Lewis Structures On your worksheet, try these elements on your own:
P Ca Ar Cl Al Cl

Al Lewis Structures On your worksheet, try these elements on your own:
P Ca Ar Cl Al Al

. Complete the Lewis Structure Worksheet You should know how to draw Lewis Structures for the first 20 elements.