1. Bohr Models are NOT Boring! Prepared by Mrs. Hunt with help from Mrs. LaRosa How to Draw Bohr Diagrams

2. 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.

3. Bohr Diagrams Find out which period (row) your element is in. www.chem4kids.com Elements in the 1 st period have one energy level. Elements in the 2 nd period have two energy levels, and so on. 1 2 3 4 5 6 7

4. Bohr Diagrams 1)Draw a nucleus. 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 N 0 = 6 Note: Round mass to nearest 1 when figuring neutrons.

5. The electron shells surrounding the nucleus each hold a particular number of electrons. Shells are named with letters: 1 st electron energy level = 2 electrons 2 nd electron energy level = 8 electrons 3 rd electron energy level= 18 electrons 4 th electron energy level = 32 electrons Remember: The outermost electron energy level of an atom can only hold 8 electrons!

6. Bohr Diagrams 1)Carbon is in the 2 nd period, so it has two energy levels, or shells. 2)Draw the energy levls around the nucleus. P + = 6 N 0 = 6

7. Bohr Diagrams 1)Add the electrons. P + = 6 N 0 = 6 2 e- 2)Carbon has 6 electrons. 3)The first energy level can only hold 2 electrons. 4)Write the number of electrons that the 2 nd energy level holds and e- for electrons an their charge. 5)How many electrons are in the outer energy level?

8. Bohr Diagrams 1)Since you have 2 electrons in the 1 st energy level, you need to add 4 more. P + = 6 N 0 = 6 2)These go in the 2 nd energy level. 3)Again, write e- and the number of electrons. 2e- 4e-

9. Bohr Diagrams 1)Check your work. 2)You should have 6 total electrons for Carbon. 3)Only two electrons can fit in the 1 st energy level. 4)The 2 nd energy level can hold up to 8 electrons. 5)The 3 rd energy level can hold 18 electrons, but the elements in the first few periods only use 8 electrons. P + = 6 N 0 = 6 2e- 4e-

10. Bohr Diagrams Try Hydrogen: Atomic Mass: 1 Atomic Number: 1 Protons: 1 Electrons: 1 Neutrons: 0 Energy Levels: 1 Valence electrons: 1 P + = N 0 =

11. Bohr Diagrams P + = 1 N 0 = 0 1e- Check Yourself. Hydrogen

12. Bohr Diagrams Try Helium P+=N0=P+=N0= Try Helium: Atomic Mass: 4 Atomic Number: 2 Protons: 2 Electrons: 2 Neutrons: 2 Energy Levels: Valence electrons: 2

13. Bohr Diagrams P + = 2 N 0 = 2 2e- Check Yourself! Helium

14. Bohr Diagrams P+=N0=P+=N0= Try Oxygen: Atomic Mass: 16 Atomic Number: 8 Protons: 8 Electrons: 8 Neutrons: 8 Energy Levels: 2 Valence electrons: 6

15. Bohr Diagrams P + = 8 N 0 = 8 6e- 2e- Check Yourslef!

16. Bohr Diagrams P+=N0= P+=N0= Try Aluminum: Atomic Mass: 27 Atomic Number: 13 Protons: 13 Electrons:13 Neutrons:14 Energy levels:3 Valence electrons:3

17. Bohr Diagrams Check Yourself! P + = 13 N 0 = 14 2e- 8e- 3e-

18. Bohr Diagrams P+=N0= P+=N0= Try Potassium: Atomic Mass: 39 Atomic Number: 19 Protons: 19 Electrons: 19 Neutrons: 20 Energy Levels: 4 Valence electrons: 1

19. Bohr Diagrams Check yourself! P + = 19 N 0 = 20 2e- 8e- 1e-

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

21. Periodic Table Study Guide By Mrs. Hunt and Mrs. LaRosa www.middleschoolscience.comwww.middleschoolscience.com 2008 How to Draw Dot Diagrams

22. 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.

23. Dot Diagrams 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

24. 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

25. Dot Diagrams 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.

27. 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.

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

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

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

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

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

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

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

35. End of Study Guide. Complete the Dot Diagrams Practice you have. You should know how to draw Dot Diagrams for the first 20 elements.