1. Chemistry The Atom © SSER Ltd.

2. Ancient Greeks were the first to come up with the idea of atoms. Democritus Democritus suggested that all matter was made of tiny indivisible particles called atoms. ( Greek “atoma” )

3. John DALTON

4. An indestructible “Dalton” atom Ha Ha! You can’t break me!!!!

5. J.J. THOMPSON

6. In 1910, Earnest Rutherford carried out experiments in which particles were fired at a thin sheet of gold. Earnest Rutherford Rutherford expected all of the particles to pass straight through...

7. Earnest Rutherford He concluded that the atom consisted of a central nucleus, which contained most of the atom’s mass, surrounded by the electrons. He also predicted the existence of neutrons in the nucleus.

8. Ernest RUTHERFORD

10. Rutherford could not explain why the negative electron didn’t fall into the positive nucleus and destroy the atom. ?

11. Neils Bohr I think I can help!

12. Neils BOHR He showed that the electrons inhabit discrete energy levels surrounding the nucleus

13. When the atom was “excited” the electron could “jump” to a higher level. When the electron came back down, it released energy in the form of light.

14. Elements emit a particular wavelength or colour as electrons jump from one shell to another Eg. Neon light

15. Neils Bohr: 1885 - 1962

16. Element 107 on the Periodic Table is called Bohrium (Bh)

17. The first electron level (shell) can hold up to 2 electrons. The second electron level (shell) can hold up to 8 electrons. The third electron level (shell) can hold up to 18 electrons. Electron Levels (Shells) = Neutron = Proton= Electron

18. C 12 Mass Number 6 Atomic Number The Carbon Atom 6 x = Protons = Electrons = Neutrons

19. In the 1920’s things changed! Although Bohr’s idea of energy levels was still accepted, his idea of planetary orbits for electrons was rejected! REJECT ! !

20. So…… What’s Next??? ????????????

21. Erwin Schrödinger He proposed the electrons appear as “clouds”. The electron has a high probability of being located within this cloud or region surrounding the nucleus.

22. 1887-1961

23. Subshells Each energy level/shell (n) contains one or more subshells – s, p, d, and f Each subshell contains an electron orbital where up to 2 electrons can most likely be found Each energy level/shell (n) contains one or more subshells – s, p, d, and f Each subshell contains an electron orbital where up to 2 electrons can most likely be found

24. 1s 2s 3s S Orbitals

25. Three p Orbitals pxpx pypy pzpz

26. p subshell can hold a maximum of 6 e-’s in p orbitals

27. Timberlake LecturePLUS 2000 d orbitals – max 10e-’s

31. 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 Writing Electron Configurations

34. Learning Check Indicate which configuration is correct for potassium. Explain. 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 6 4s 1 D. 1s 2 2p 8 3s 1 E.1s 2 2s 2 2p 6 3s 2 3p 7 Indicate which configuration is correct for potassium. Explain. 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 6 4s 1 D. 1s 2 2p 8 3s 1 E.1s 2 2s 2 2p 6 3s 2 3p 7

35. Solution Potassium: A. 2, 2, 8, 5 B. 2, 8, 3 C. 2, 8, 5 D. 2, 6, 7 Potassium: A. 2, 2, 8, 5 B. 2, 8, 3 C. 2, 8, 5 D. 2, 6, 7

36. Learning Check Using the periodic table, write the complete electronic configuration for each: A. Cl B. Sr +2 C. I Using the periodic table, write the complete electronic configuration for each: A. Cl B. Sr +2 C. I

37. Solution

38. Learning Check A. The final two notations for Co are 1) 3p 6 4s 2 2) 4s 2 4d 7 3) 4s 2 3d 7 B. The final three notations for Sn are 1) 5s 2 5p 2 4d 10 2) 5s 2 4d 10 5p 2 3) 5s 2 5d 10 5p 2 A. The final two notations for Co are 1) 3p 6 4s 2 2) 4s 2 4d 7 3) 4s 2 3d 7 B. The final three notations for Sn are 1) 5s 2 5p 2 4d 10 2) 5s 2 4d 10 5p 2 3) 5s 2 5d 10 5p 2

39. Solution A. The final two notations for Co are 3) 4s 2 3d 7 B. The final three notations for Sn are 2) 5s 2 4d 10 5p 2 A. The final two notations for Co are 3) 4s 2 3d 7 B. The final three notations for Sn are 2) 5s 2 4d 10 5p 2

40. Learning Check A. Number of electrons in a p orbital 1) 1e2) 1e or 2e3) 3e B. Number of orbitals in a p subshell 1) 12) 23) 3 C. Number of orbitals in 4d subshell 1) 12) 33) 5 D. Number of electrons (maximum) in a 3d subshell 1) 2e2) 5e3) 10e A. Number of electrons in a p orbital 1) 1e2) 1e or 2e3) 3e B. Number of orbitals in a p subshell 1) 12) 23) 3 C. Number of orbitals in 4d subshell 1) 12) 33) 5 D. Number of electrons (maximum) in a 3d subshell 1) 2e2) 5e3) 10e

41. Solution A. Number of electrons in a p orbital 2) 1e or 2e B. Number of orbitals in a p subshell 3) 3 C. Number of orbitals in 4d subshell 3) 5 D. Number of electrons in a 3d subshell 3) 10e A. Number of electrons in a p orbital 2) 1e or 2e B. Number of orbitals in a p subshell 3) 3 C. Number of orbitals in 4d subshell 3) 5 D. Number of electrons in a 3d subshell 3) 10e