Block 26: Th 11/7 or F 11/8

1. Block 26: Th 11/7 or F 11/8 • Sapling #11 due T 11/12 • Flame test lab due next class • Debrief flame test

2. Quantum Mechanical Model, Electron Configuration and Orbital Diagrams Add to your electrons notes Draw a line and put today’s date: 11/7 or 11/8

3. Quantum Mechanical Model Max Planck and Werner Heisenberg expanded upon Bohr’s model There are energy levels, but they are not circular orbits They are regions in which you may find electrons in the electron cloud Bohr Quantum Image from the Higher Education Academy Physical Sciences Centre

4. Electrons are organized in three ways 1st = Energy levels each atom contains energy levels; which generally correspond to the rows of the PT It’s like an address! 2nd = Sublevels each energy level contain sublevels; they are divided into blocks called s, p, d and f 3rd = Orbitals each sublevel contain orbitals; an orbital is the space occupied by two (a pair of) electrons

5. Electron Sublevels

6. What do orbitals look like? orbital on s sublevel(one per sublevel) (remember two electrons fit in each orbital) orbitals on p sublevel (three per sublevel)

7. What do orbitals look like? orbitals on d sublevel(five per sublevel)

8. What do orbitals look like? orbitals on f sublevel(seven per sublevel)

9. Since sublevels and orbitals are too complicated to draw all the time, we simplify with orbital diagrams. Each orbital is represented by a box. Each electron is represented by an up or down arrow.  (means 2 electrons)

10. s sublevel s sublevel has one orbital, so we draw one box. p sublevel p sublevel has 3 orbitals, so we draw 3 boxes.

11. d sublevel d sublevel has 5 orbitals, so we draw 5 boxes. f sublevel f sublevel has 7 orbitals, so we draw 7 boxes.

12. Orbital and sublevel information is like a map, telling you where an electron can be found in an atom. There are three rules that govern why an electron will be in one sublevel rather than another: • Pauli Exclusion Principle • Hund’s Rule • Aufbau Principle

13. Pauli Exclusion Principle: No two electrons can have the same set of quantum numbers (basically, “orbital address”). What that means is that 2 electrons may occupy one orbital, but they must have opposite spin direction. This is why we draw electrons as arrows facing opposite directions when they share a box: 

14. Hund’s Rule:Before 2 electrons will occupy the same orbital of a sublevel, there must be at least one electron in every orbital of that sub level.   Example: 4 electrons in a d sublevel WRONG -This is not stable.Electrons repel each other.     RIGHT -This is stable. Hund’s Rule paraphrased – spread them out before you pair them up!

15. Aufbau Principle: Each electron must occupy the lowest energy orbital available. Not all sublevels and orbitals have the same energy! s  p  d  f energy increases 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p This chart shows the order that electrons fill sublevels. Although the d and f sublevels are on lower energy levels, they have high energy and do not fill until after the s and p for higher energy levels.

16. Using the Aufbau Diagram • Add electrons in the order of the arrows you drew • Remember sublevels and electrons • sholds 2 electrons • pholds 6 electrons • dholds 10 electrons • fholds 14 electrons

17. The number of columns in each block corresponds to the number of electrons that fit in that sublevel

18. You can use the periodic table like a game board to see the order in which the sublevels fill. Each square can mean the position of one electron The period number tells you the energy level The block tells you the sublevels

19. An element’s location within that block tells you how many electrons it has in that sublevel

20. Example: Nitrogen is in the 3rd column of the p block.It has 3 electrons in the p sublevel

21. Example: Manganese has 25 electrons. Draw its orbital diagram. Use Aufbau Principle to determine sublevel and orbital order. 1s 2s 2p 3s 3p 4s 3d

22. Example: Manganese has 25 electrons. Draw its orbital diagram.  1s     2s 2p     3s 3p       4s 3d Use Pauli Exclusion Principle to place arrows facing the opposite direction in each orbital.

23. Your Turn: Nickel has 28 electrons. Draw its orbital diagram. 1s 2s 2p 3s 3p 4s 3d

24. Orbital Notation Practice Website

25. History of the Periodic Table More information can be foundin Chapter 6 of your text

26. Antoine Lavoisier Image from Science Shorts 1790 –– He was the first to organize the elements. At the time, only 23 elements were known. He arranged them into a list. Distinguished metals from nonmetals. Image by Peter van der Krogt  

27. John Newlands • 1864 –– At this time, 70 elements were known. • The list was too unorganized for that many elements, so he created a table. • He noticed that properties of the elements repeated every 8 elements when they were arranged by increasing atomic mass. • He called this observation the Law of Octaves. • This law was not widely accepted, but it was mostly correct. Photo from chemsoc

28. Predict which element will go here. octave

29. octave

30. Predict which element will go here. octave

31. What does the Newlands Table have in common with the current periodic table? octave

32. Elements with the same number of Valence electrons are in the same row. octave

33. Lothar Meyer and Dmitri Mendeleev In 1869 Photo from chemsoc Photo from jergym Czech Republic • They worked on the same type of table, but not together. • Mendeleev published his ideas first, so he usually gets the credit.

34. Lothar Meyer and Dmitri Mendeleev They arranged the periodic table by atomic mass horizontally rather than vertically.

35. Lothar Meyer and Dmitri Mendeleev Predict which element will go here.

36. Lothar Meyer and Dmitri Mendeleev

37. What does the Mendeleev Table have in common with the current periodic table?

38. Columns were arranged so that all elements in a column have similar chemical and physical properties. What do these three elements have in common? They are all Noble/ Inert Gases

39. Lothar Meyer and Dmitri Mendeleev They were able to predict the existence of undiscovered elements based on blank spaces in the periodic table.

40. Henry Moseley Moseley observed that some elements seemed to be in the wrong column based on their activity. Photo from chemsoc

41. Henry Moseley For example, Nickel reacts more like Platinum.

42. Moseley decided to order the table by Atomic Number rather than atomic mass.

43. Moseley decided to order the table by Atomic Number rather than atomic mass.

44. Glen Seaborg 1940 - synthesized Np and Pu Decided they must go in a new block of the Periodic table called Actinides. Seaborg was awarded a Nobel Prize in 1951.

45. Review Who made the first organized chart of elements? Antione Laviosier, list of 23 elements

46. Review Who made the first chart in Table form? • John Newlands, based on his Law of Octaves

47. Review Lothar Meyer and Dmitri Mendeleev, but they did not work together Who first organized the table in horizontal rows?

48. Review Who arranged the table the way it is used today? Henry Moseley, arranged it by atomic number