Electron Configurations

1. Electron Configurations Init: 10/07/09 by Daniel R. Barnes

2. http://www.youtube.com/watch?v=u9VMfdG873E&NR=1&feature=endscreenhttp://www.youtube.com/watch?v=u9VMfdG873E&NR=1&feature=endscreen

3. SWBAT . . . . . . describe the shape, number, position, and energy rank of the various kinds of orbitals.

4. You should already have learned by now that atoms are made mostly of . . . empty space empty space empty space

5. However, that space isn’t quite empty. There are ELECTRONS whizzing around the space surrounding an atom’s nucleus empty space However, electrons don’t orbit a nucleus exactly the same way that a planet orbits the sun. The truth is far more bizarre than that. Electrons in an atom occupy energy states called “orbitals”, but there are some serious differences between an electron “orbital” and the orbit of a planet. At any given time, a planet has a definite location in space, and it also has a definite speed and direction of motion. An electron, on the other hand, has neither. An electron merely has probabilities of being in certain locations and probabilities of moving with certain velocities.

6. This is a traffic ticket.

7. You can’t write a traffic ticket for an electron, because you can’t know its position and momentum simultaneously. The more certain your measurement of one is, the less certain the reality of the other one becomes. This is known as the “Heisenberg uncertainty principle”. If you can’t know an electron’s position and motion at the same time, how can you possibly describe its “orbit”?

8. The moon orbits the earth. Nice and simple, isn’t it?

9. Newton’s laws of motion allow us to predict the moon’s location and motion with pinpoint accuracy. Therefore, we were able to aim our Apollo spacecraft perfectly so that they could “rendezvous” with the moon. Anything less than perfect accuracy would have meant dead astronauts. An electron’s “orbit” is nothing like the orbit of the moon. Electron motion is totally unpredictable. In fact, it’s indescribable.

10. Electron orbitals are nothing like planetary orbits.

12. The lowest electron energy state in an atom is the “1s” orbital. The 1s orbital is often represented as a spherical region of space. The 1s orbital doesn’t truly have an outer boundary, but we draw one anyway. 1s The meaning of the yellow line is this: When an electron is in the 1s orbital, it is 90% likely to be inside the yellow line. The electron has a 10% probability to be outside of this “boundary”. In the 1s orbital, the electron is more likely to be found closer to the nucleus than farther from it. This is represented by the red color being most intense in the center and fading to black toward the outside.

13. . . . and extremely unlikely, though still possible, to be this far away from that positive “nut” in the middle of the atom. The electron is very likely to be here, in the center, near the nucleus . . . . . . not quite as likely to be here, at a medium distance from the nucleus . . . . . . very unlikely to be here, far from the nucleus . . . The meaning of the yellow line is this: When an electron is in the 1s orbital, it is 90% likely to be inside the yellow line. It has a 10% probability to be outside of this “boundary”. The essence of the 1s orbital is that the electron is more likely to be found closer to the nucleus than farther from it. This is represented by the red color being most intense in the center and fading to black toward the outside.

14. Until you attempt to “observe” or “measure” the position of the electron, it exists in all possible places at once, at none of them in particular.. It’s not until you measure its position that the electron makes up its mind and decides to be in a particular place.

15. Yes. Run while you can, little man.

16. At that point, as you become more certain about its location, you become less certain about the motion of the electron. The very reality of the electron’s motion becomes indistinct as you distinguish the electron’s location.

17. Run from the quantum mechanics terror bird.

18. The 1s orbital can only hold two electrons. The third and fourth electrons in an atom exist in the “2s” orbital. The 2s orbital is just like the 1s, only larger. 1s 2s

19. The 1s and the 2s orbitals don’t lie next to each other. They share a common center point. Let’s superimpose them on top of each other, like they’re supposed to be. 1s 2s

20. An atom with more than four electrons will have one or two electrons in the atom’s 2p orbitals. “p” orbitals are made of two lobes each. Some people think a p orbital looks like a peanut. 1s 2s 2p

21. 1s 2s 2px

22. 2py 1s 2s 2px

23. 1s 2s 2px 2py

24. 2pz 1s 2s 2px 2py

25. 1s 2s 2px 2py 2pz

26. This is what an atom with ten electrons looks like. 1s2 2s2 2p6 Its electron configuration would be written as you see above.

27. With the “boundaries” erased, it looks more like this . . . It’s not exactly the neat little solar system Rutherford envisioned, is it? Instead, it’s a hazy cloud of probability. It’s a misty ghost with an indistinct existence. 1s2 2s2 2p6

29. The 2nd shell of an atom consists of two sublevels, the 2s and the 2p. The 2p sublevel consists of three orbitals: 2px, 2py, and 2pz. Each p orbital can hold two electrons, one “spinning up” and one “spinning down”.

31. An “s” sublevel is made of one orbital A “p” sublevel is made of three orbitals A “d” sublevel is made of five orbitals An “f” sublevel is made of seven orbitals

32. An “s” sublevel is made of one orbital  s2 when full A “p” sublevel is made of three orbitals  p6 when full A “d” sublevel is made of five orbitals  d10 when full An “f” sublevel is made of seven orbitals  f14 when full

33. CA Chemistry Standard 1g*: Students know how to relate the position of an element in the periodic table to its quantum electron configuration and its reactivity with other elements in the table

34. The Diagonal Rule WARNING: As with all things you are taught in school, the diagonal rule is an over-simplification of reality. It is a reasonable predictor of the “aufbau” order for electron orbital filling, but it is not to be trusted 100%.

35. The Diagonal Rule 7i 6h 7h 5g 6g 7g 4f 5f 6f 7f 3d 4d 5d 6d 7d 2p 3p 4p 5p 6p 7p 1s 2s 3s 4s 5s 6s 7s First, we build the staircase . . .

36. The Diagonal Rule 7i 6h 7h 5g 6g 7g 4f 5f 6f 7f 3d 4d 5d 6d 7d 2p 3p 4p 5p 6p 7p 1s 2s 3s 4s 5s 6s 7s Then, we draw the diagonal lines . . .

37. The Diagonal Rule 7i 6h 7h Finally, we follow the diagonal lines to get the aufbau sequence . . . 5g 6g 7g 4f 5f 6f 7f 3d 4d 5d 6d 7d 2p 3p 4p 5p 6p 7p 1s 2s 3s 4s 5s 6s 7s 1s 2s 2p 3s 3p 4s 3d 4p 5s 6s 4f 5d 6p 7s 5f 6d 7p 4d 5p

38. 9/16/2014 Tuesday SWBAT . . . Explain how the periodic table is structured. HOMEWORK: ALL: 6.1 sxn assmt HONORS: Also 5.3 all s p d WARM-UP: What is the significance of the “staircase” on the periodic table I gave you? f GRADING PROGRESS: Chapter 4 Scratch = 20%

39. SWBAT . . . . . . make electron configurations ACTUAL LESSON NEEDED!

41. the end