1. 4-2 Notes Parts of the Atom Chapter 4, Lesson 2

3. Electrons and Energy Levels An energy level is a region in space corresponding to a certain energy through which an electron moves (similar to a planet’s orbit).

4. Electrons and Energy Levels Each energy level can hold a certain number of electrons according to these rules: Bohr’s Model

5. Electrons and Energy Levels –The first level holds 2 electrons, the second level holds 8 electrons. Neon’s atomic number = 10 It has 10 protons. It has 10 electrons. 10 Ne Neon 20.18

6. Electrons and Energy Levels –The lowest level is filled first. Ne 10 Ne Neon 20.18

7. Electrons and Energy Levels –The lowest level is filled first. Ne 10 Ne Neon 20.18

8. Electrons and Energy Levels –The lowest level is filled first. Ne 10 Ne Neon 20.18

9. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

10. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

11. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

12. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

13. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

14. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

15. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

16. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

17. Electrons and Energy Levels –The second level has no electrons until the first level is full. 10 Ne Neon 20.18 Ne

18. Electrons and Energy Levels –The last energy level may or may not be filled to the max. Ne 10 Ne Neon 20.18 3 Li Lithium 6.94 Li

19. Electrons and Energy Levels An element will react with other elements to try to receive a full outer energy level. (also known as “completing the octet”)

20. Electrons and Energy Levels This diagram shows how electrons are placed in the elements with atomic numbers 1–10 (according to Bohr’s model)

21. Electrons and Energy Levels Different numbers of electrons in outer energy level results in different elements.

22. Electrons and Energy Levels Unreactive elements have a full outer energy level.

23. Electrons and Energy Levels Elements with incomplete outer energy levels are likely to form compounds. 

24. Electrons and Energy Levels Atomic Model http://glencoe.mcgraw-hill.com/sites/0078741858/student_view0/brainpop_movies.html#

25. Electron Cloud Model Today scientists think of an electron in an atom as being in an electron cloud, which is a region surrounding an atomic nucleus where an electron is most likely to be found. Electron Cloud Model

26. Electrons are more likely to be near the nucleus because they are attracted to the positive charge of the protons.

28. Elements that do not react with other elements must have ____. Acompletely filled energy levels Bexcited electrons Cempty energy levels Dthe same number of protons and neutrons 4.2 Discovering Parts of the Atom 1.A 2.B 3.C 4.D

29. Atoms of the same element always have the same number of ____. Aelectrons Bneutrons Cions Dprotons