1. The Nature of Light (Honors)
Dual Nature of Light:
behaves as both waves and as particles (depending on what type of experiment is being performed.)
Speed of Light: light waves travel at same velocity
C = 3.0 x 108 meters/sec
What is Light?
Greatest Discovery in Physics: (Duality of Light)

2. Electromagnetic Spectrum
Spectral lines can come from all areas of EM Spectrum.
Visible colors make up only a small part

3. Which wave has higher energy?
EM waves carry different amounts of energy based upon their wavelength and frequency.
Wavelength (λ): distance between two peaks of a wave
Frequency (γ): number of peaks that pass per second. (Hertz (Hz) or cycles/sec)
Which wave has higher energy?
Relationship of Frequency, Wavelength and Energy of colored line

4. Calculating Energy of a Spectral Line (HONORS)
STEP 1:
Given wavelength of spectral line find it’s frequency.
c = λ x ү
c = the speed of light = 3 x 108 meters/sec
λ = wavelength (in meters)
1 x 10-9 meter = 1 nm 1 x meter = 1 Angstrom
ү = frequency of the wave (Hertz or waves/sec, s-1)

5. Calculating Energy of a Spectral Line (HONORS)
STEP 2:
Using frequency find energy of the line (in Joules)
E = h x ү
E = energy (Joules)
h = Planck's constant = 6.63 × kg x m2 / sec
ү = frequency of the wave (Hertz or waves/sec, s-1)

7. How are Electrons Organized?
Energy Levels
Sublevels
Orbitals
Spin
The Electron Hotel

8. Energy Levels (1-7) Energy Levels 1 2 3 4 5 6 7
Electrons exist at different distances from the nucleus.
Energy Levels
Lowest energy Highest energy
Closest to nucleus Farthest from Nucleus

9. Sublevels (s, p, d, f) Energy levels have certain number of sublevels.
Energy Level Sublevels Possible
1 s
2 s, p
3 s, p, d
4 s, p, d, f
5 s, p, d, f, (g)
6 s, p, d, f, (g, h)
7 s, p, d, f, (g, h, i)
Theoretical sublevels

10. Energy of Sublevels Sublevels have different levels of energy. s p d f
Lowest energy Highest energy

11. Orbitals in Sublevels Sublevels contain different numbers of orbitals.
Maximum 2 electrons can exist in an orbital.
Sublevel # of Orbitals Max e- in Sublevel
s e-
p e-
d e-
f e-

12. Aufbau Diagram Shows: Follow the “diagonal rule”
order of electron filling
order of electron energy
Follow the “diagonal rule”

13. Writing Electron Configurations
Let’s write some electron configurations!
Ex: Magnesium
Follow the diagonal rule

14. Some sublevels “overlap”
Results in certain sublevels having higher energy than others
Ex: 3d has higher energy than 4s
Electron Configurations for Atoms
Extremely Corny Song About Electron Configurations

15. Electron Spin Electrons in an orbital spin in opposite directions
Pauli Exclusion Principle:
In order for two electrons to occupy the same orbital, they must have opposite spins.
Otherwise they create a magnetic field!

16. Orbital Diagrams Show electrons in individual orbitals
s = 1 orbital, p = 3 orbitals, d = 5 orbitals, f = 7 orbitals
“Hund’s Rule for Orbital Filling”
When filling orbitals in a sublevel, place one electron in each orbital before adding the second.

18. Shapes of Orbitals Orbitals come in different shapes and sizes.
Region of highest probability of finding an electron.
Orbitals Shape & Energy & Spectral Line

19. Probability cloud has a spherical shape
s Orbital
Probability cloud has a spherical shape

20. p Orbitals (px, py, pz) “Dumbell” shape
Three p orbitals can exist, on the x, y, z axis in space

21. Five possible d orbitals exist

22. Seven possible f orbitals exist

23. Valence Electrons
Usually found in the s and p sublevels of highest occupied energy level.
How many valence electrons?
Draw a Lewis Dot Diagram of this element.
1s22s22p63s23p64s23d104p2

24. Kernel 1s22s22p63s23p3 All electrons except the valence
How many kernel electrons?
How many valence?

25. Excited vs. Ground State
Electron configuration you would normally write by following the order of filling
Lowest to highest energy.
Excited State:
one or more electrons have jumped up to a higher energy level.
Ex: 1s22s22p63s23p54s23d104p3

26. Atom vs. Ion Configurations
Ions: atoms that have gained or lost electrons.
Figure out how many electrons the ion has then write configuration.
Ex: 20Ca+2 has 18 electrons
1s22s22p63s23p6 = 18 electrons DONE!
Electron Configurations for Ions

27. Isoelectronic Species
Atoms and ions that have the same number of electrons.
Ex: Ar, K+1, Ca+2, P-3, O-2, Cl-1
All have 18 electrons!

28. Impossible Configurations
Break the rules.
Ex: 1s22s22p63s22d103p64s23d104p2
Ex: 1s22s32p63s23p6

29. s, p, d, f, “Blocks”
Indicates what sublevel is being filled last in the atom

30. Some Exceptions to Orbital Filling (HONORS)
When d and f sublevels get filled near the end of a configuration we sometimes see exceptions.
It is more stable for the orbitals of the d and f sublevels to be half filled or filled completely than to be one shy.
Electrons from the sublevel below get “promoted” up to make the atom more stable
Ex: Copper

31. Crash Course Chemistry: The Electron
(13 minutes)
Quantum Mechanics and the Bohr Model (6 minutes)
**Developing Modern Atomic Theory (6min)
Rutherford to Bohr to the Modern Model
The Uncertainty Principle (6min) Honors
Probability & Chance of Finding an e- and Orbital Shapes