The Nature of Light (Honors)

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? • https://www.youtube.com/watch?v=eCVPhjHh57E • Greatest Discovery in Physics: (Duality of Light) • https://www.youtube.com/watch?v=XB-iLRsq8A8

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

3. 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 http://employees.oneonta.edu/viningwj/sims/plancks_equation_s.html

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 10-10 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 × 10-34 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) • Electrons exist at different distances from the nucleus. • Energy Levels 1 2 3 4 5 6 7 Lowest energy Highest energy Closest to nucleus Farthest from Nucleus

9. Sublevels (s, p, d, f) • Energy levels have certain number of sublevels. Energy LevelSublevels 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 1 2 e- p 3 6 e- d 5 10 e- f 7 14 e-

12. Aufbau Diagram • Shows: • 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 http://employees.oneonta.edu/viningwj/sims/atomic_electron_configurations_s1.html Extremely Corny Song About Electron Configurations http://www.youtube.com/watch?v=Vb6kAxwSWgU&safe=active

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 • http://www.youtube.com/watch?v=fKYso97eJs4

19. 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. d Orbitals • Five possible d orbitals exist

22. f Orbitals • 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 • All electrons except the valence 1s22s22p63s23p3 • How many kernel electrons? • How many valence?

25. Excited vs. Ground State • 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 http://employees.oneonta.edu/viningwj/sims/atomic_electron_configurations_s2.html

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) • http://www.youtube.com/watch?v=rcKilE9CdaA • Quantum Mechanics and the Bohr Model (6 minutes) • http://www.youtube.com/watch?v=-YYBCNQnYNM **Developing Modern Atomic Theory (6min) Rutherford to Bohr to the Modern Model http://youtu.be/45KGS1Ro-sc The Uncertainty Principle (6min) Honors Probability & Chance of Finding an e- and Orbital Shapes http://www.youtube.com/watch?v=Fw6dI7cguCg