1. Electron Arrangement:
electrons (e) are found in energy levels outside of the nucleus.
Energy level(s) = Orbit(s) or Shell(s) where e are found.
(a.k.a. “Principal Energy Level(s)”)

4. Period = Horizontal (left  right) row in the periodic table.
Period # = the # of occupied energy levels (E.L.)
Q: How many periods are there on the periodic table???

5. There are a total of 7 possible E.L.
1st Energy level (1st E.L.) = closest to nucleus.
has LEAST energy of all E.L.
7th E.L. has MOST energy of all E.L.

6. e only occupy the orbits of lowest E.L. first.
Eg. e fill up 1st E.L.  fill up 2nd E.L. . . .  fill up 7th E.L.

7. Formula for # of e allowed in each E.L.:
n = E.L.
(Eg. n = 6  6th E.L.)
** 2n2 = # of e that can occupy E.L. “n”. **

8. Q.1. How many e can occupy E.L. 1?

9. Q.2. Fill in the following Table. (show work on the side)
Energy level (n)
max. # of electrons allowed
(2n2) 1 2 3 4 5 6 7

10. Octet Rule
Octet Rule – The valence E.L. can never hold more than 8 e-.
Valence E.L. = outermost shell
Valence electrons = electrons on the valence (outermost) shell.

11. Octet Rule (cont’d)
All Elements WANT to have a FULL valence energy level (shell)
Full valence shell = 8 e- (or 2 e- if 1st E.L.)
H and He only want 2 valence electrons
Why???

12. Octet Rule (Cont’d) Eg. draw the Bohr model of potassium-38 (38K)
Q.1) How many valence e- does K have?
Q.2) How many valence e- does K want?
Q.3) What is the easiest (least energy) way for K to obtain this???
Energy Levels

13. Electron Configuration
Electron Configuration: The # of electrons according to the shell they’re in.
Write out the # of e- according to the shell they’re in.
Eg H Li
Electron Config. = Electron Config. =

14. Symbol
Electron Config. 1 11 2 12 3 13 4 14 5 15 6 16 7 17 8 18 9 19 10 20

15. Ground State vs. Excited State
“Ground State” and “Excited State”
refers to the state of the atom based on location of electrons.

16. Ground State Ground State: LOW Energy STABLE
Electrons occupy LOWEST E.L. (Energy Levels).
LOW Energy
STABLE
Why???
** P.T. shows ground state only!!! **

17. Excited State Excited State:
Electron “jumps” to HIGHER energy level (temporarily)

18. Excited State “jump up”  ABSORBS energy
“sugar high”
“fall down”  RELEASES energy (as LIGHT!)
“sugar low”
UNSTABLE
HIGH Energy
Exciting an electron

19. Excited State
Drawing of atom in the excited state:

20. Excited State Flame Test Demo – Flame Tests (Cu, Li, K, Na, Sr)
Formed by the heating of metal ions, using a flame.
Demo – Flame Tests (Cu, Li, K, Na, Sr)
Q.) Why does the flame cause this effect?

21. Excited State Spectral Lines: “the DNA code of elements”
Formed by Gases (must use electricity)
Spectral lines
***Demo – Spectral lines
***must use 3-D glasses.

22. Excited State – Spectral Lines
Q.: Based on the line spectra, which of the following elements are contained in the unknown sample?

23. Excited vs. Ground State
Label each of the following as being in the ground state or excited state:
*(see if you can convert excited  ground)
A.)
B.) 1-8
C.)
D.)
E.)

24. Electron Dot Diagram Electron Dot Diagram:
Illustrates the element symbol surrounded by the valence electrons.
Eg.1. Draw the Electron Dot Diagram:
H C Ca

25. Electron-dot Diagrams (cont’d)
Ne B N Ba
S F Hg Cl

26. Groups Groups: Q. What do elements in the same group have in common???
Vertical (up and down) columns on the P.T.
Q. What do elements in the same group have in common???