Unit 1: Intro to Earth/Environmental Science

1. Unit 1: Intro to Earth/Environmental Science How to Draw Bohr Diagrams and Lewis Dot Structures Al

2. Bohr Diagrams • Find your 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.

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

4. Bohr Diagrams • Draw a nucleus with the element symbol inside. • Carbon is in the 2nd period, so it has two energy levels, or shells. • Draw the shells around the nucleus. C

5. Bohr Diagrams • Add the electrons. • Carbon has 6 electrons. • The first shell can only hold 2 electrons. C

6. Bohr Diagrams • Since you have 2 electrons already drawn, you need to add 4 more. • These go in the 2nd shell. • Add one at a time -starting on the right side and going counter clock-wise. C

7. Bohr Diagrams • 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. C

8. How to Draw Lewis Dot Structures

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

10. 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

11. Groups - Review Group 8 = 8 electrons Group 1 = 1 electron Except for He, it has 2 electrons 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” www.chem4kids.com

12. 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

13. 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

15. Bohr Diagrams Try the following elements on your own: • H • He • O • Al • Ne • K C

16. Bohr Diagrams Try the following elements on your own: • H – 1 electron • He • O • Al • Ne • K H

17. Bohr Diagrams Try the following elements on your own: • H • He - 2 electrons • O • Al • Ne • K He

18. Bohr Diagrams Try the following elements on your own: • H • He • O - 8 electrons • Al • Ne • K O

19. Bohr Diagrams Try the following elements on your own: • H • He • O • Al - 13 electrons • Ne • K Al

20. Bohr Diagrams Try the following elements on your own: • H • He • O • Al • Ne - 10 electrons • K Ne

21. Bohr Diagrams Try the following elements on your own: • H • He • O • Al • Ne • K - 19 electrons K

22. Bohr Diagrams End of Study Guide. You should know how to draw a Bohr Diagram for the first 20 elements.