1. Warm Up: 9/22 (Back of NB) What are Bohr Models? How do you draw a Bohr Model? (use step-by-step instructions)

2. Bohr Models 1.Write your element’s symbol in the center. 2.Determine the number of electrons you should draw. 3.Use the 2-8-18 rule to draw the correct number of electrons on the shells!

3. Valence Electrons The electrons in the outer-most energy level of an atom.

4. Lewis Structures Lewis Structures are representations of atoms that only show the electrons on the outer- most energy level. Also known as “electron-dot diagram.”

5. How to draw a Lewis Structure: 1.Find the element on the periodic table 2.Determine the number of valence electrons you should draw. 3.Draw a dot to represent each valence electron around the element’s symbol. (maximum of 8 electrons)

6. Periodic Table Study Guide www.middleschoolscience.comwww.middleschoolscience.com 2008 How to Draw Lewis Structures

7. Lewis Structures 1)Find your element on the periodic table. 2)Determine the number of valence electrons. 3)This is how many electrons you will draw.

8. 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. www.chem4kids.com

9. 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” www.chem4kids.com

10. Lewis Structures 1)Write the element symbol. 2)Carbon is in the 4 th group, so it has 4 valence electrons. 3)Starting at the right, draw 4 electrons, or dots, counter- clockwise around the element symbol.

11. Lewis Structures 1)Check your work. 2)Using your periodic table, check that Carbon is in the 4 th group. 3)You should have 4 total electrons, or dots, drawn in for Carbon.

12. Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

13. Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

14. Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

15. Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

16. Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

17. Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

18. Lewis Structures On your worksheet, try these elements on your own: a)H b)P c)Ca d)Ar e)Cl f)Al

19. Octet Rule Elements tend to combine in a way that each atom has 8 electrons. 8 = full and happy valence shell!