1. Valence Electrons and Oxidation Numbers Chemistry Dr. May

2. 1 H 1 Region where electron is likely to be found Nucleus Electron Cloud Model of the Hydrogen Atom  + 1s 1

3. Hydrogen Gas

4. Hydrogen Gas (H 2 )

5. Hydrogen atom1s2s2p3s3p4s H - 1 EC VE Ox # Ion  1s 1 1 +1 H +1 gives H 2 SO 4 With SO 4  2

6. O O O O S HH

7. Helium atom1s2s2p3s3p4s He - 2  EC VE Ox # Ion 1s 2 2 0 none 

8. 4 He 2 Region where the 2 electrons are likely to be found Nucleus Electron Cloud Model of the Helium Atom  + +  1s 2

9. Lithium atom1s2s2p3s3p4s Li - 3  EC1s 2 VE Ox # Ion  2s 1 1 +1 Li +1 With SO 4  2 gives Li 2 SO 4

10. 7 Li 3 Region where the 1s electrons are likely to be found Nucleus Electron Cloud Model of the Lithium Atom  + +  1s 2 2s 1 Region where the 2s electron is likely to be found  +

11. Beryllium atom1s2s2p3s3p4s Be - 4  EC1s 2 VE Ox # Ion gives BeSO 4 With SO 4  2 2s 2 2 +2 Be +2 

12. Electron Art Berylium

13. The Beryllium Atom 4 9 1s 2 2s 2 Be 4 protons 4 electrons 5 neutrons

14. Boron atom1s2s2p3s3p4s B - 5  EC1s 2 2s 2 VE Ox # Ion  2p 1 3 +3 B +3 With O  2 gives B 2 O 3

15. Carbon atom1s2s2p3s3p4s C - 6   EC1s 2 2s 2 VE Ox # Ion CO 2 and CCl 4  2p 2 4 Has 4 electrons to share Covalent

16. Carbon Atom 12 C 6

17. Nitrogen atom1s2s2p3s3p4s N - 7   EC1s 2 2s 2 VE Ox # Ion Has 5 electrons to share Covalent NCl 5 and N 2 O 5  5 2p 3

18. An Atom Nitrogen

19. Oxygen atom1s2s2p3s3p4s O - 8   EC1s 2 2s 2 VE Ox # Ion  2p 4 6 22 O2O2 With K +1 gives K 2 O

20. Oxygen atom nucleus electrons

21. Fluorine atom1s2s2p3s3p4s F - 9   EC1s 2 2s 2 VE Ox # Ion  2p 5 7 11 F1F1 With K +1 gives KF

22. Neon atom1s2s2p3s3p4s Ne - 10   EC1s 2 2s 2 VE Ox # Ion  2p 6 8 0 none

23. Sodium atom1s2s2p3s3p4s Na - 11  EC1s 2 2s 2 2p 6 VE Ox # Ion  3s 1 1 +1 Na +1 With SO 4  2 gives Na 2 SO 4

24. Magnesium atom1s2s2p3s3p4s Mg - 12   EC1s 2 2s 2 2p 6 VE Ox # Ion  3s 2 2 +2 Mg +2 With SO 4  2 gives MgSO 4

25. Quantum Model Quantum Model 2s orbital 1s orbital Nucleus 2p orbitals 3s orbital             1s 1 1s 2 1s 2 2s 1 1s 2 2s 2 1s 2 2s 2 2p 1 1s 2 2s 2 2p 2 1s 2 2s 2 2p 3 1s 2 2s 2 2p 4 1s 2 2s 2 2p 5 1s 2 2s 2 2p 6 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 3s 2 H HeLiBeBCNOFNeNaMg

26. Aluminum atom1s2s2p3s3p4s Al - 13  EC1s 2 2s 2 2p 6 3s 2 VE Ox # Ion  3p 1 3 +3 Al +3 With SO 4  2 gives Al 2 (SO 4 ) 3

27. Al +3 H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O Hydrated Al +3

28. Silicon atom1s2s2p3s3p4s Si - 14   EC1s 2 2s 2 2p 6 3s 2 VE Ox # Ion  3p 2 4 Silicon has 4 electrons to share CovalentSiO 2 and SiC

29. Phosphorus atom1s2s2p3s3p4s P - 15   EC1s 2 2s 2 2p 6 3s 2 VE Ox # Ion  3p 3 5 Phosphorus has 5 electrons to share Covalent PCl 5 and P 2 O 5

30. Sulfur atom1s2s2p3s3p4s S - 16   EC1s 2 2s 2 2p 6 3s 2 VE Ox # Ion gives Na 2 S  3p 4 6 22 S2S2 With Na +1

31. Chlorine atom1s2s2p3s3p4s Cl - 17   EC1s 2 2s 2 2p 6 3s 2 VE Ox # Ion  3p 5 7 11 Cl  1 With Al +3 gives AlCl 3

32. Argon atom1s2s2p3s3p4s Ar - 18   EC1s 2 2s 2 2p 6 3s 2 VE Ox # Ion  3p 6 8 0 none

33. +18 Argon = s electrons = p electrons Energy level 1  Energy level 2  Energy level 3  1s 2 2s 2 2p 6 3s 2 3p 6

34. Potassium atom1s2s2p3s3p4s K - 19  EC1s 2 2s 2 2p 6 3s 2 3p 6 VE Ox # Ion  4s 1 1 +1 K +1 With S  2 gives K 2 S

35. Calcium atom1s2s2p3s3p4s Ca - 20   EC1s 2 2s 2 2p 6 3s 2 3p 6 VE Ox # Ion  4s 2 2 +2 Ca +2 With SO 4  2 gives CaSO 4

36. The End This presentation was created for the benefit of our students by the Science Department at Howard High School of Technology Please send suggestions and comments to rmay@nccvt.k12.de.us