Calendar. October 23, Chapter 5 Notes Waves.notebook Waves vocab waves ws. quiz PSAT. Blank. elements test. demo day

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1 Calendar Sunday Monday Tuesday Wednesday Thursday Friday Saturday Waves vocab waves ws 20 PSAT make notecards 7th quiz elements test demo day Blank 1

2 The Nature of Matter: By the early 20 th century it was understood by most scientists that energy and matter were separate. Atoms were matter and light was energy... Light behaved as a wave... Oct 13 9:53 AM 2

3 What did scientists know about the atom by the early 20 th century? Oct 14 12:44 PM 3

4 What are Waves? What do you think of? Types of Waves: Parts of waves: What are wave made out of? Sep 26 1:11 PM 4

5 Parts of Waves: Wavelength Crest Amplitude Trough Sep 26 1:12 PM 5

6 Parts of Waves: Crest: Top of the wave Trough: Bottom of the wave Wavelength Crest Amplitude Trough Wavelength (λ): Is the shortest distance between equivalent points on a continuous wave (crest to crest or trough to trough) commonly measured in meters, centimeters or nanometers Frequency (υ): Is the number of waves that pass a given point per second. Hertz (Hz) is the SI unit for frequency Amplitude: Is the wave's height from the origin to a crest, or from the origin to a trough. (wavelength and frequency do not affect amplitude) Oct 21 10:06 AM 6

7 Oct 14 9:36 AM 7

8 Electromagnetic radiation: Light is defined as electromagnetic radiation, a form of energy that exhibits wavelike behavior as it travels through space Radio waves Examples: microwaves infrared waves visible light ultraviolet waves x rays gamma rays Oct 24 2:34 PM 8

9 Electromagnetic Spectrum: A spectrum that includes all forms of electromagnetic radiation, with the only difference in the types of radiation being their frequencies and wavelengths ROYGBIV Oct 24 2:47 PM 9

10 Wave Mathematical Relationships C = λ * υ λ Wavelength υ frequency C Speed of light Speed of light is 3.00 x 10 8 m/s This speed is constant for all electromagnetic waves inside a vacuum (space) Note: As frequency increases, wavelength decreases (inverse relationship) Note: As frequency increases, energy of the wave increases Practice: What is the frequency of an X ray with a wavelength of 1.15 x m? Oct 24 2:19 PM 10

11 HOm e wo r k! Wavelength Practice: What is the frequency of an X ray with a wavelength of 1.15 x m? Oct 14 9:14 AM 11

12 Light as a wave failed to explain: Why heated objects emit only certain frequencies of light These colors correspond to different wavelength and frequencies black body phenomena Why do some metals emit electrons when light at a given temperature shines on them (photoelectric effect)? Oct 24 2:54 PM 12

13 Photoelectric Effect Some metals will eject electrons form their surface with light of a certain frequency (or higher) hits their surface Light was affecting matter...how? Oct 24 7:43 PM 13

14 Max Planck (1900) A German physicist was searching for an explanation of these phenomena. He found that matter could either gain or lose energy but only in small specific amounts called he called quanta Quantum is the minimum amount of energy that can be gained or lost by an atom Oct 24 6:13 PM 14

15 Energy of a Quantum Planck came up with a relationship between the energy of a quantum and the frequency of a wave E = h * υ E Energy of a quantum h Planck's Constant h = x J*s υ frequency of the wave This showed scientists that these quanta (packets of energy) were whole number multiples of hυ hυ 2hυ 3hυ 4hυ 5hυ 6hυ 7hυ 8hυ Oct 24 7:29 PM 15

16 Stair step analogy Oct 13 11:53 AM 16

17 Albert Einstein (1905) Duality of light light can be both a wave and a particle It is a beam of bundles of energy called photons Photons a massless particle that carries a quantum of energy. This energy depends on the frequency of the photons E Photon = hυ E photon = Energy of the photon h = Plank's Constant υ= frequency The blue color in some fireworks occurs when copper chloride is heated to approximately 1500K and emits blue light with a frequency 6.67 x Hz. How much energy does one photon of this light carry? Oct 24 8:07 PM 17

18 Oct 16 3:16 PM 18

19 The blue color in some fireworks occurs when copper chloride is heated to approximately 1500K and emits blue light of wavelength 4.50x10 2 nm. how much energy does one photon of this light carry? Oct 16 10:16 AM 19

20 Oct 16 9:17 AM 20

21 Warm up: What two phenomena were not explainable by Rutherford's atomic model and scientist's understanding of matter and energy at the turn of the 20 th century? What did Planck discover? How did Einstein explain Planck's discovery? RED RIBBON WEEK! Sep 26 1:08 PM 21

22 Atomic Emission Spectra: the set of frequencies of the electromagnetic waves emitted by atoms of the element Each element has a very specific range of colors that are emitted These are used to identify elements and elements within compounds Scientists did not have a scientific reason to explain this... Oct 13 11:07 AM 22

23 Niels Bohr (1913) Studied the hydrogen atom and, based off of Planck's and Einstein's concepts of quantized energy, determined that the atom only had certain allowable energy states Lowest possible energy state is called Ground State When the atom absorbs energy, it is said to be in an Excited State Sep 26 12:55 PM 23

24 Bohr's Model of the Atom Bohr suggested that the electrons around the hydrogen atom could only be allowed in certain circular orbits around the nucleus The smaller the electron's orbit, the lower the atom's energy state or energy level The larger the electron's orbit, the higher the atom's energy level Sep 26 12:55 PM 24

25 Bohrs Atomic Quantum orbit number Corresponding Orbit atomic energy Radius (nm) level First n = E1 Relative Energy Second n = E2 = 4E1 Third n = E3 = 9E1 Fourth n = E4 = 16E1 Fifth n = E5 = 25E1 Sixth n = E6 = 36E1 Seventh n = E7 = 49E1 Quantum Number: The number Bohr gave to each orbit around the atom Sep 26 12:56 PM 25

26 Energy State Ground State for Hydrogen is when hydrogen's single electron is in the first energy level or the first quantum level The hydrogen atom does not give off energy in the ground state Once energy is added the single electron moves up to a higher energy orbit (such as n = 2) making the atom in an excited state The electron will fall back into its original quantum level (ground state) and release the energy as a photon Since these quanta are set, only set energies can be absorbed and emitted by the atom, therefore only specific frequencies are emitted by the atom What did this explain? Sep 26 12:56 PM 26

27 Atomic Emission Spectra Electrons around an atom's nucleus will absorb energy in quanta, the electrons will then jump up and fall back down to what is called ground state and release that same amount of energỵ This energy has a specific frequency which can be seen as colors; meaning the frequency of the photons release is within the visible light of the electromagnetic spectrum Oct 24 8:24 PM 27

28 Therefore the wavelength of light emitted by excited electrons could be used to determine the energy absorbed by the electron. E= hυ C = λ * υ What is the energy absorbed by the electron on the diagram? λ = 3.45 x 10 9 meters Oct 13 11:11 AM 28

29 Louis de Broglie (1924) If light can have both wave and particle like characteristics, then matter (electrons) can behave as both Predicted that all moving particles have wave like characteristics (including cars or baseballs) λ = h/mυ λ = Wavelength h = Planck's constant υ = frequency m = mass Why can we not see the wavelength of a moving baseball? (Do the math) Sep 26 12:57 PM 29

30 Werner Heisenberg ( ) Stated that it is impossible to take any measurement of an object without disturbing the object Heisenberg uncertainty principle: states that it is fundamentally impossible to know precisely both the velocity and position of an electron at the same time Meaning Bohr's defined orbits were not accurate Sep 26 12:57 PM 30

31 Erwin Schrodinger (1926) Austrian Physicist Quantum Mechanical model of the atom: the atomic model in which electrons are treated as waves This allowed for scientists to determine particular volumes of space around the nucleus in which the probability of finding an electron is very high Atomic Orbital: the probable location of an electron within an atom; it is 3 D in shape Sep 26 12:57 PM 31

32 Atomic Orbitals Principal quantum number (n) number of the atomic orbitals. (also called Principal energy level) As n increases, the orbitals become larger and have more energy These levels contain what are called energy sublevels The first energy level contains 1 sublevel; the second energy level contains 2 sublevels,the third energy level contains 3 sublevels, etc. There are a total of 4 sublevels labeled s, p, d and f These sublevels are then broken down further into orbitals A single orbital can only hold 2 electrons total Meaning if there are 3 orbitals there can be a total of 6 electrons in that sublevel Sep 26 12:59 PM 32

33 Oct 22 9:47 AM 33

34 S Sublevel The s sublevel has a spherical shape The s sublevel only has one orbital and therefore s sublevel can only hold two electrons Sep 26 12:59 PM 34

35 P Sublevel The p sublevel is a dumb bell shape The p sublevel contains 3 orbitals and therefore contains 6 electrons total Sep 26 1:00 PM 35

36 Oct 22 8:45 AM 36

37 Electron Configuration Chap. 5.3 Sep 26 1:02 PM 37

38 Review Energy levels can be found by looking at what on the periodic table? Sep 26 1:03 PM 38

39 d sublevel The d sublevel has two shapes; one that looks like two dumb bells put together and the other is like a single dumb bell The d sublevel contains 5 orbitals and therefore can hold up to 10 electrons Sep 26 1:00 PM 39

40 f sublevel The f sublevel has a very complex shape The f sublevel contains 7 orbitals and therefore contains 14 electrons Sep 26 1:00 PM 40

41 Basic goal: Break the energy levels down into sub levels and orbitals! Energy levels Sub levels (s, p, d, and f) Orbitals Only 2 electrons Sep 26 1:03 PM 41

42 Periodic breakdown of levels and sublevels Notice that the energy level 1 contains only 1 sublevel (s), energy level 2 contains 2 sublevels (s and p), energy level 3 contains 3 sublevels (s, p, and d), and energy level 4 contains 4 sublevels (s, p, d, and f) Which is the order of the orbitals: s, p, d, and f Sep 26 1:02 PM 42

43 Electron Configuration This is the arrangement of electrons in an atom Review How many electrons can the s sublevel hold? How many electrons can the p sublevel hold? How many electrons can the d sublevel hold? How many electrons can the f sublevel hold? Where can each of the sublevels be found on the periodic table? Sep 26 1:03 PM 43

44 Rules for Electron Configuration/orbital diagrams There are three rules that must be followed while writing electron configurations Rule 1: Aufbau Principle Each electron occupies the lowest energy orbital available "fill up left to right" Rule 2: Pauli Exclusion Principle A maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins "ups with downs, no ups w ups or downs with downs" Rule 3: Hund's rule Single electrons with the same spin must occupy each equal energy orbital before additional electrons with opposite spins can occupy the same orbital "ups before downs" Sep 26 1:04 PM 44

45 A. 1s 2s 2p 3s 3p 4s 3d B. 1s 2s 2p 3s 3p 4s 3d C. 1s 2s 2p 3s 3p 4s 3d 1s 2s 2p 3s 3p 4s 3d Nov 12 1:16 PM 45

46 Rule 1: Aufbau Principle Each electron occupies the lowest energy orbital available This means that you must first be able to determine the order of energy levels, sub levels and the orbitals within those sub levels Energy levels move in the order of periods down the periodic table Order: 1, 2, 3, 4, 5, 6 and 7 Sub levels are in the order of s, p, d, and f and how they appear on the periodic table 1s 2s 3s 4s 5s 6s 7s 3d 4d 5d 6d Notice that the d level and f level are "behind" the s and p level 4f 5f 2p 2p 3p 4p 5p 6p 7p Sep 26 1:05 PM 46

47 Rule 2: Pauli Exclusion Principle A maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins Remember that the sub levels contain orbitals. S sublevel contains 1 orbital, p sublevel contains 3 orbitals, d sublevel contains 5 orbitals, and f sublevel contains 7 orbitals s sublevel can only hold 2 electrons p sublevel can only hold 6 electrons d sublevel can only hold 10 electrons f sublevel can only hold 14 electrons This means that an energy level that contains ALL sublevels can only contain 32 electrons all together Sep 26 1:05 PM 47

48 p S d f Sep 26 1:05 PM 48

49 Jun 15 9:29 AM 49

50 Lets say we want to write the electron config for Nitrogen S d p f Sep 26 1:06 PM 50

51 Practice: Write the electron diagram for the following elements: Cobalt Phosphorus Oxygen Argon Calcium Silver Sep 26 1:06 PM 51

52 Rule 3: Hund's rule / Pauli Exclusion principle Single electrons with the same spin must occupy each equal energy orbital before additional electrons with opposite spins can occupy the same orbital Lets look at our electrons configuration for Nitrogen 1s 2 2s 2 2p 3 1s 2s 2p This is called an orbital diagram Sep 26 1:06 PM 52

53 Oct 22 3:16 PM 53

54 Practice: Write the orbital diagram for the following elements: Manganese Potassium Gallium Neon Sep 26 1:07 PM 54

55 Noble gas notation: Where are the noble gasses on the periodic table? Noble gas notation makes writing electron configs and orbital diagrams easier (and shorter) Let say we wanted to write out the electron configuration for Bromine Now instead of write ALL of that, determine the noble gas that comes BEFORE Bromine and write everything in the configuration that comes AFTER that point Sep 26 1:07 PM 55

56 Practice: Write the Nobel gas notation for the following elements: Sodium Iron Arsenic Sulfur Silicon Sep 26 1:08 PM 56

57 1s 2 2s 2 2p 6 3s 2 3p 4 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 1 1s 2 2s 2 2p 6 3s 2 1s 2 2s 2 2p 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 Oct 22 10:18 AM 57

58 Nov 12 1:39 PM 58