Bohr Models are NOT Boring!

Prepared by Mrs. Hunt with help fromMrs. LaRosa

How to Draw Bohr Diagrams

Bohr Diagrams

1) Find the element on the periodic table.2)Determine the number of electrons--it is the

same as the atomic number.3)This is how many electrons you will draw.

Bohr Diagrams• Find out which period

(row) your element is in.

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•Elements in the 1st period have one energy level.•Elements in the 2nd period have two energy levels, and so on.

1

2

3

4

5

6

7

Bohr Diagrams1) Draw a nucleus with

the element symbol inside.

C 2)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.

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 electrons2 = L shell = 8 electrons3 = M shell = 8 electrons4 = N shell = 18 electrons5-7 = 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

1) Carbon is in the 2nd period, so it has two energy levels, or shells.

2) Draw the shells around the nucleus.

CP+ = 6

N0 = 6

Bohr Diagrams1) Add the electrons.

CP+ = 6

N0 = 6

2 e-

2) Carbon has 6 electrons.3) The first shell can only

hold 2 electrons.4) Write the number of

electrons that shell holds and e- for electrons an their charge.

5) How many electrons are in the outer shell?

Bohr Diagrams

1) Since you have 2 electrons in the first shell, you need to add 4 more.

CP+ = 6

N0 = 6

2) These go in the 2nd shell.

3) Again, write e- and the number of electrons.

2e-

4e-

Bohr Diagrams1) Check your work.

2) You should have 6 total electrons for Carbon.

3) Only two electrons can fit in the 1st shell.

4) The 2nd shell can hold up to 8 electrons.

5) 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.

CP+ = 6

N0 = 6

2e-

4e-

Bohr Diagrams

Try Hydrogen:Atomic Mass:Atomic Number:Protons:Electrons:Neutrons:Shells:Valence electrons:

HP+ =

N0 =

Bohr Diagrams

HP+= 1

N0= 0

1e-

Check Yourself.

Bohr Diagrams

Try Helium

HeP+=

N0=

Try Helium:Atomic Mass:Atomic Number:Protons:Electrons:Neutrons:Shells:Valence electrons:

Bohr Diagrams

HeP+= 2

N0= 2

2e-

Check Yourself!

Bohr Diagrams

OP+=

N0=

Try Oxygen:Atomic Mass:Atomic Number:Protons:Electrons:Neutrons:Shells:Valence electrons:

Bohr Diagrams

OP+= 8

N0= 8

6e-

2e-

Check Yourslef!

Bohr Diagrams

AlP+=

N0=

Try Aluminum:Atomic Mass:Atomic Number:Protons:Electrons:Neutrons:Shells:Valence electrons:

Bohr Diagrams

Check Yourself!

AlP+= 13

N0= 14

2e-

8e-

3e-

Bohr Diagrams

KP+=

N0=

Try Potassium:Atomic Mass:Atomic Number:Protons:Electrons:Neutrons:Shells:Valence electrons:

Bohr Diagrams

Check yourself!

KP+= 19

N0= 20

2e-

8e-

8e-1e-

Bohr Diagrams

You should know how to draw a Bohr Diagram for

the first 20 elements.

Periodic Table Study Guide

By Mrs. Hunt and Mrs. LaRosa

www.middleschoolscience.com 2008

How to Draw Lewis Structures

Lewis Structures

1) Find the element on the periodic table.2) Determine the number of valence electrons.3) 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.

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Groups - Review

•Each column is called a “group”

•Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.

Except for He, it has 2 electrons

•The electrons in the outer shell are called “valence electrons.”

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Lewis Structures1) Write the element

symbol.2) Carbon is in the 4th

group, so it has 4 valence electrons.

3) Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol.

Lewis Structures

1) Check your work.2) Using your periodic

table, check that Carbon is in the 4th group.

3) You should have 4 total electrons, or dots, drawn in for Carbon.

Lewis Structures

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Lewis Structures

On your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

End of Study Guide.

Complete the Lewis Structure Worksheet

You should know how to draw Lewis Structures for the first 20

elements.