Exploring Light Waves and the Quantum Model of Electrons in Atoms

1. Chapter 4 Electrons In Atoms

2. Properties of Light • ___________________: a form of energy that exhibits wavelike behavior as it travels through space. (ex. Visible light, x-rays, UV, IR, radio) • ____________________: all forms of electromagnetic radiation together make up the spectrum. 4-2

3. Properties of Light

4. Characteristics of Waves • There are 4 main characteristics of waves: • 1) ___________: The height of the wave measured from it’s origin to it’s peak. When you increase the intensity, or brightness of light, you are increasing it’s amplitude. 4-4

5. Characteristics of Waves 4-3

6. Characteristics of Waves • 2)________________: the distance between corresponding points on adjacent waves. Wavelength is designated by the Greek symbol __________. Wavelength = ___ 4-6

7. Characteristics of Waves 4-5

8. Characteristics of Waves • 3) ___________: the number of waves that pass a given point in a specific time. Measured in cycles per second (cycle/second, or s-1) The SI unit for this is Hertz. 1.0 Hz = 1.0 s-1 Frequency is designated by the Greek symbol ___. Frequency = ____ 4-8

9. Characteristics of Waves

10. Characteristics of Waves • 4)_________: the speed of light is constant. It is rounded to _________m/s. The speed of light is represented by the letter ____. ___ = λυ 4-10

11. The Photoelectric Effect • Refers to the emission of _________ from a metal when light shines on the metal. • __________: the minimum amount of energy that can be lost or gained by an atom • ____________, a German physicist studied quanta of light and found: 4-11

12. The Photoelectric Effect E(energy) = _____ Where h is Plank’s Constant and has a value of 6.6262 x 10-34 Js 4-12

13. The Photoelectric Effect Einstein expanded upon this to propose that light has a ______________, acting as a _______ under some circumstances and a ____________ under others. __________: a particle of electromagnetic radiation having zero mass and carrying a quantum of energy. 4-13

14. Line Emission Spectrum ______________: the lowest energy state of an atom _____________: a state in which an atom has a higher potential energy than it has in it’s ground state. 4-14

15. Line Emission Spectrum _____________________: a graph that indicates the degree to which a substance emits radiant energy with respect to ______________. ______________________: the emission of a continuous range of frequencies of electromagnetic radiation. 4-15

16. H Emission Spectrum _____________: a Danish physicist who proposed a hydrogen-atom model that linked the atom’s electron to photon emission. (electrons circle the nucleus in “_______”) 4-16

17. H Emission Spectrum Emission Line Spectrum: a graph that indicates the degree to which a substance emits radiant energy with respect to wavelenth. Continuous Spectrum: the emission of a continuous range of frequencies of electromagnetic radiation. 4-17

18. H Emission Spectrum Emission Line Spectrum: a graph that indicates the degree to which a substance emits radiant energy with respect to wavelenth. Continuous Spectrum: the emission of a continuous range of frequencies of electromagnetic radiation. 4-18

19. The Quantum Model ____________________________: states that it is impossible to determine simultaneously both the ___________ and _______________ of an electron or any other particle. ___________________: describes mathematically the wave properties of electrons and other very small particles. 4-19

20. The Quantum Model ______________________: specify the properties of atomic orbitals and the properties of electrons in orbitals. Quantum numbers were developed based on the ____________________, developed by Austrian physicist Erwin Shrödenger. 4-20

21. The Quantum Model __________________________: indicates the main energy level occupied by the electron. Values are positive integers only (1, 2, 3, 4 with 1 being the lowest energy level closest to the nucleus) _______________________: indicates the shape of the orbital. Values are 0, 1…n-1) 4-21

22. The Quantum Model l = 0 = sl = 1 = p l = 2 = d l = 3 = f l = 0 = S l = 1 = p l = 2 = d l = 3 = f 4-21

23. The Quantum Model Magnetic Quantum Number (m): indicates the orientation of an orbital around the nucleus. Values, including zero, are –l to +l l = 0 = s orbital has only one orientation (sphere) l = 1 = p has three orientations l = 2 = d has five orientations l = 3 = f has seven orientations 4-23

24. The Quantum Model

25. The Quantum Model

26. The Quantum Model

27. The Quantum Model ________________________: indicates the two fundamental spin states of an electron in an orbital. Values are +1/2 or -1/2. ______________________: the arrangement of electrons in an atom. 4-27

28. Orbital Filling Diagrams There are ____________, named after the scientists that discovered them, that govern the filling of these orbitals with electrons… • The ________________: an electrons occupies the lowest energy orbital that can receive it. 4-28

29. Orbital Filling Diagrams 2) The ________________________: no two electrons in the atom can have the same set of four quantum numbers. 3) _______________: Electrons occupy equal energy orbitals so that a maximum numbered of unpaired electrons results, and all e- in singly occupied orbitals must have the same spin. 4-29

30. Orbital Filling Diagrams When using this form, each electron is designated as an _______ ________ pointing up or down to show opposite spins. Each orbital is designated with a labeled line: ____ or __ __ __ 1s 2p ____________lines show multiple orbitals (1 for s, 3 for p, 5 for d) 4-30

31. Orbital Filling Diagrams Orbitals fill going _____________ each period (_____) on the periodic table, from the lowest energy level up. (Aufbau). Don’t forget, when they pair, they have ____________ (Pauli), but they won’t pair until each available orbital has an unpaired electron in it first (Hund) 4-31

32. Orbital Filling Diagrams 4-32 4-31

33. Orbital Filling Diagrams _____________, with one electron, would have an orbital filling diagram of:  1s __________, with 2 electrons, would be:  1s Now your at the end of the first period, start again in the 2nd period with 2s… 4-33

34. Orbital Filling Diagrams Lithium:  1s 2s Be:  1s 2s B:  _ _ 1s 2s 2p

35. Orbital Filling Diagrams Which of these would be correct for oxygen (with 8 e-): O: ? 1s 2s 2p OR  1s 2s 2p ____________ is correct, the _________ example violates the Pauli Exclusion Principle. 4-35

36. Practice Write the orbital filling notation for the following elements: • Be:_________________________ • F:__________________________ • Ar:_________________________ • Cu:_________________________ 4-36

37. Electron Configurations Now your ready to write electron configurations. These are simply the orbital diagrams written out with superscripts: Lithium:  1s 2s would be written out as 1s2 2s1 Be:  1s 2s would be written out as 1s2 2s2 B:  _ _ 1s 2s 2p would be written out as 1s22s22p1 4-37

38. Practice Write the electron configuration for the following elements: • Mg:________________________ • N:_________________________ • Cr:________________________ • Cl:________________________ 4-38

39. Electron Configurations ___________________: refers to an outer main energy level occupied by eight e- • Once a __________ is complete at the end of a period, you can write subsequent configurations as having the _______ of the ___________ with the additional ___________ electrons. • Sodium Na would have a noble gas notation of: Ne3s1 4-39

40. Practice Write the noble gas notation for the following elements: • Na:_________________________ • Sb:_________________________ • Y:__________________________ • F:__________________________ 4-40

41. Ch. 4 The End 4-41