2. Electrons and Orbitals

3. Quantum Mechanics Describes the arrangement of electrons in atoms in terms of: Main or principal energy levels (n) Orbitals (space occupied within the atom) How many electrons in each orbital. Basically, gives an address for every electron in an atom.

4. Principal Energy Levels (n) Contain electrons that are Close in energy Similar distance from nucleus Have values of n = 1, 2, 3, 4, 5, 6…..

6. Orbitals Orbitals exist within an energy level All electrons in an orbital have the same energy Designated s, p, d, f.. energy: s<p<d<f

8. Electron Locations Main Energy Orbitals in Levelsthe energy level n=44s, 4p, 4d, 4f n=33s, 3p, 3d n=22s, 2p n=11s

9. S P D F

10. Electrons Allowed All electrons in the same orbital have the same energy. Within orbitals are sub-orbitals (part of an orbital….like apartments in a building). Each sub-orbital holds 2 electrons. s orbital 1 sub-orbital = 2 electrons max. p orbital 3 sub-orbitals = 6 electrons max. d orbital 5 sub orbitals = 10 electrons max. f orbital 7 sub-orbitals = 14 electrons max.

11. S P D F

12. Timberlake LecturePLUS 2000 Electron Configuration List of subshells containing electrons Written in order of increasing energy Superscripts give the number of electrons Example: Electron configuration of neon number of electrons 1s 2 2s 2 2p 6 Energy levelorbital

13. S P D F

14. Writing Electron Configurations H He Li C S

15. Writing Electron Configurations H1s 1 He 1s 2 Li 1s 2 2s 1 C1s 2 2s 2 2p 2 S1s 2 2s 2 2p 6 3s 2 3p 4

16. Learning Check S2 Which if the following is the correct electron configuration for Chlorine? A.1s 2 2s 2 2p 6 3s 1 B. 1s 2 2s 2 2p 6 3s 2 3p 6 C.1s 2 2s 2 2p 6 3s 2 3p 5 D. 1s 2 2p 8 3s 1 E.1s 2 2s 2 2p 6 3s 2 3p 7

17. Solution E2 C.1s 2 2s 2 2p 6 3s 2 3p 5

18. Timberlake LecturePLUS 2000 Learning Check S3 Using the periodic table, write the complete electronic configuration for each: A. Be B. F C. Mg

19. Timberlake LecturePLUS 2000 Solution S3 Using the periodic table, write the complete electronic configuration for each: A. Be 1s 2 2s 2 B. F 1s 2 2s 2 2p 5 C. Mg 1s 2 2s 2 2p 6 3s 2

20. Orbital A 3 dimensional space around a nucleus in which electrons are most likely to be found Shape represents electron density (not a path the electron follows) Each sub-orbital can hold up to 2 electrons.

21. s orbitals 1s 2s 3s

22. Three p Sub-Orbitals pxpx pzpz pypy

23. p orbitals

24. d sub-orbitals

25. Review Questions A. Maximum number of electrons in p orbitals a) 2b) 3 c) 6 B. Number of suborbitals in a p orbital. a) 1b) 2c) 3 C. Maximum number of electrons in an S orbital a) 1b) 2c) 6

26. Solution A. Maximum number of electrons in p orbitals c) 6 B. Number of suborbitals in a p orbital. c) 3 C. Maximum number of electrons in an S orbital b) 2

27. Review Questions 1) What scientist discovered the nucleus of the atom? 2) Who said that electrons travel in ORBITS around the nucleus, like planets around the sun? 3) Where in an atom will you find neutrons? Who discovered them?

28. Review Questions 1) What scientist discovered the nucleus of the atom? Rutherford 2) Who said that electrons travel in ORBITS around the nucleus, like planets around the sun?Bohr 3) Where in an atom will you find neutrons? Who discovered them? In the nucleus, tightly packed with the protons; Chadwick