1. HSTMr.Watson Chapter 8 Electron Configuration and Periodicity

2. HSTMr.Watson Orbitals region of probability of finding an electron around the nucleus 4 types => s p d f maximum of 2 electrons per orbital

3. HSTMr.Watson Pure Atomic Orbitals shape # of orbitals / energy level s spherical 1 p dumbbell 3 d complex 5 f very complex 7

4. HSTMr.Watson Pauli Exclusion Principle

5. HSTMr.Watson Electronic Configurations The shorthand representation of the occupancy of the energy levels (shells and subshells) of an atom by electrons.

6. HSTMr.Watson Electronic Configuration shells=>energy levels subshells=>orbitals

7. HSTMr.Watson

8. HSTMr.Watson Regions by Electron Type

9. HSTMr.Watson Electron Filling Order Diagram 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 7s

10. HSTMr.Watson Electronic Configuration H atom 1 electron 1s 1

11. HSTMr.Watson Electronic Configuration He atom 2 electrons 1s 2

12. HSTMr.Watson Electronic Configuration Li atom 3 electrons 1s 2, 2s 1

13. HSTMr.Watson Electronic Configuration Cl atom 17 electrons 1s 2, 2s 2, 2p 6, 3s 2, 3p 5

14. HSTMr.Watson Electronic Configuration As atom 33 electons 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 2, 3d 10, 4p 3 or [Ar] 4s 2, 3d 10, 4p 3

15. HSTMr.Watson Mn: [Ar]4s 2 3d ? How many d electrons does Mn have? 4, 5, 6

16. HSTMr.Watson

17. HSTMr.Watson Electronic Configuration negative ions add electron(s), 1 electron for each negative charge

18. HSTMr.Watson Electronic Configuration S -2 ion (16 + 2)electrons 1s 2, 2s 2, 2p 6, 3s 2, 3p 6

19. HSTMr.Watson Electronic Configuration positive ions remove electron(s), 1 electron for each positive charge

20. HSTMr.Watson Electronic Configuration Mg +2 ion (12-2)electrons 1s 2, 2s 2, 2p 6

21. HSTMr.Watson How many valence electrons are in Cl, [Ne]3s 2 3p 5 ? 2, 5, 7

22. HSTMr.Watson For Cl to achieve a noble gas configuration, it is more likely that electrons would be added electrons would be removed

23. HSTMr.Watson

24. HSTMr.Watson Trends in the Periodic Table atomic radius ionic radius ionization energy electron affinity

25. HSTMr.Watson Atomic Radius decrease left to right across a period – as nuclear charge increases, number of electrons increase; however, the nucleus acts as a unit charge while the electrons act independently, pulling electrons towards the nucleus, decreasing size

26. HSTMr.Watson Atomic Radius increase top to bottom down a group – each additional electron “shell” shields the outer electrons from the nuclear charge Z eff = Z - S whereZ eff => effective nuclear charge Z => nuclear charge, atomic number S => shielding constant

27. HSTMr.Watson Atomic Radius increases from upper right corner to the lower left corner

28. HSTMr.Watson Atomic Radius vs. Atomic Number

29. HSTMr.Watson Atomic Radius

30. HSTMr.Watson Ionic Radius same trends as for atomic radius positive ions smaller than atom negative ions larger than atom

31. HSTMr.Watson Ionic Radius Isoelectronic Series series of negative ions, noble gas atom, and positive ions with the same electronic confiuration size decreases as “positive charge” of the nucleus increases

32. HSTMr.Watson Ge is a semiconductor. If half of the Ge atoms of a sample of Ge are replaced with Ga atoms, with what element should the other half of the Ga atoms be replaced in order for this new compound to be isoelectronic with Ge? Sn, As, Se

33. HSTMr.Watson Ionization Energy energy necessary to remove an electron to form a positive ion low value for metals, electrons easily removed high value for non-metals, electrons difficult to remove increases from lower left corner of periodic table to the upper right corner

34. HSTMr.Watson Ionization Energies first ionization energy energy to remove first electron from an atom second ionization energy energy to remove second electron from a +1 ion etc.

35. HSTMr.Watson Ionization Energy vs. Atomic Number

36. HSTMr.Watson Electron Affinity energy released when an electron is added to an atom same trends as ionization energy, increases from lower left corner to the upper right corner metals have low “EA” nonmetals have high “EA”

37. HSTMr.Watson Magnetism Result of the spin of electrons diamagnetism - no unpaired electrons paramagnetism - one or more unpaired electrons ferromagentism - case of paramagnetism where the substance retains its magnetism

38. HSTMr.Watson Magnetism Paramagnetism Ferromagnetism Without applied field With applied field