1.  Bell Ringer: How do you know something exists if you have never seen it before? Important Vocabulary  Inference  Indirect evidence  Bell Ringer: How do you know something exists if you have never seen it before? Important Vocabulary  Inference  Indirect evidence Nature of Science

7. The Black Box Lab  Purpose  Materials  Procedure  Results Table (20 pts)  Post Lab Questions (30 pts)  Purpose  Materials  Procedure  Results Table (20 pts)  Post Lab Questions (30 pts)

10. Results (20 pts) Box #InferencesModel Example a) b) c) 1 a) b) c)

11. Post Lab Questions (30pts) 1.How did you construct your model of what was in the boxes? 2.How do you know if something exists if you have never seen it before? 3.How does this lab relate to the scientific method? 4.To create a more accurate model, what would you want to do next without looking inside the boxes? 5.How do you think scientists use or have used empirical evidence to create models? (hint: think about topics in this class) 1.How did you construct your model of what was in the boxes? 2.How do you know if something exists if you have never seen it before? 3.How does this lab relate to the scientific method? 4.To create a more accurate model, what would you want to do next without looking inside the boxes? 5.How do you think scientists use or have used empirical evidence to create models? (hint: think about topics in this class)

12. Contents of Each Box Box 1- Wooden block Box 2 - 3 Pennies Box 3 - 2 Straws Box 4 - 10 Stickers Box 5 - Pill Canister Box 6 – 2 Rubber bands Box 7 - 1 Dice Box 8- 10 Beads Box 9 - 10 Lima Beans Box 10 - 2 Cotton Balls Box 1- Wooden block Box 2 - 3 Pennies Box 3 - 2 Straws Box 4 - 10 Stickers Box 5 - Pill Canister Box 6 – 2 Rubber bands Box 7 - 1 Dice Box 8- 10 Beads Box 9 - 10 Lima Beans Box 10 - 2 Cotton Balls

13. Closure: watch video “have you ever seen an atom?”“have you ever seen an atom? Exit Pass – how does today’s lab relate to the discovery of the atom? Closure: watch video “have you ever seen an atom?”“have you ever seen an atom? Exit Pass – how does today’s lab relate to the discovery of the atom? What does an atom actually look like?

14.  It is now your turn to do some research…  You will be assigned a scientist to become an expert on  This scientist had an impact on the historical development of the atom  YOUR JOB: give a creative, informative poster on your scientist and how they influenced the historical development of the atom  You are then going to share your poster with others to inform them about your scientist.  It is now your turn to do some research…  You will be assigned a scientist to become an expert on  This scientist had an impact on the historical development of the atom  YOUR JOB: give a creative, informative poster on your scientist and how they influenced the historical development of the atom  You are then going to share your poster with others to inform them about your scientist. Historical Scientists Jigsaw Activity

15. Textbook Info  Dalton – pg 77-78  Thomson – pg 79  Rutherford – pg 81  Bohr – pg 91  DeBroglie – pg 91  Dalton – pg 77-78  Thomson – pg 79  Rutherford – pg 81  Bohr – pg 91  DeBroglie – pg 91

16. Atoms New section in table of contents

17. Aristotle & Democritus  First philosophers to start thinking about the atom and its component  Smallest divisible component vs. indivisible particle  First philosophers to start thinking about the atom and its component  Smallest divisible component vs. indivisible particle

18. Dalton  Billiard Ball Model  Provided evidence for how we know atoms exist  Billiard Ball Model  Provided evidence for how we know atoms exist

19. EQ 1: How do we know atoms exist?  KC 1: Law of definite proportions – a chemical compound always contains the same elements in exactly the same proportions by weight or mass  KC 2: Law of conservation of mass  KC 3: Law of multiple proportions – when 2 elements combine to form 2 or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers  KC 1: Law of definite proportions – a chemical compound always contains the same elements in exactly the same proportions by weight or mass  KC 2: Law of conservation of mass  KC 3: Law of multiple proportions – when 2 elements combine to form 2 or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers

20. EQ 2: What are the five postulates of Dalton’s atomic theory  The ancient Greeks tried to explain matter, but the scientific study of the atom began with John Dalton in the early 1800's.

21.  KC 1: All matter is composed of extremely small particles called atoms, which cannot be subdivided, created, or destroyed  Many ancient scholars believed matter was composed of such things as earth, water, air, and fire.  Many believed matter could be endlessly divided into smaller and smaller pieces  KC 1: All matter is composed of extremely small particles called atoms, which cannot be subdivided, created, or destroyed  Many ancient scholars believed matter was composed of such things as earth, water, air, and fire.  Many believed matter could be endlessly divided into smaller and smaller pieces EQ 2: What are the five postulates of Dalton’s atomic theory

22.  KC 2: Atoms of a given element are identical in their physical and chemical properties  KC 3: Atoms of different elements differ in their physical and chemical properties  KC 2: Atoms of a given element are identical in their physical and chemical properties  KC 3: Atoms of different elements differ in their physical and chemical properties EQ 2: What are the five postulates of Dalton’s atomic theory

23.  KC 4: Atoms of different elements combine in simple, whole-number ratios to form compounds  KC 5: In chemical reactions, atoms are combined, separated, or rearranged but never created, destroyed, or changed  KC 4: Atoms of different elements combine in simple, whole-number ratios to form compounds  KC 5: In chemical reactions, atoms are combined, separated, or rearranged but never created, destroyed, or changed EQ 2: What are the five postulates of Dalton’s atomic theory

24. Thomson  Plum pudding model  Introduced the idea that electrons are located outside the nucleus  Plum pudding model  Introduced the idea that electrons are located outside the nucleus

25. Rutherford  Discovered the nucleus  Used the gold foil experiment  Discovered the nucleus  Used the gold foil experiment

26. EQ 3: What model of the atom will we use?  KC 1: Bohr suggested that electrons move in circular orbitals around the nucleus  Bohr’s model of the atom gives us a good starting point for understanding more about the atom  KC 1: Bohr suggested that electrons move in circular orbitals around the nucleus  Bohr’s model of the atom gives us a good starting point for understanding more about the atom

27. EQ 3: What model of the atom will we use? KC 2: How to draw a Bohr model of an atom 1)Find your element on the periodic table. 2)Determine the number of electrons – it is the same as the atomic number. 3)Determine the number of circular orbits the atom has. 4)Add electrons = atomic number - 1 st shell can hold two - 2 nd and 3 rd can hold eight KC 2: How to draw a Bohr model of an atom 1)Find your element on the periodic table. 2)Determine the number of electrons – it is the same as the atomic number. 3)Determine the number of circular orbits the atom has. 4)Add electrons = atomic number - 1 st shell can hold two - 2 nd and 3 rd can hold eight

28. Bohr model of the atom  Elements in the 1 st period have one energy level.  Elements in the 2 nd period have two energy levels, and so on.

29. C Bohr model of the atom  Draw a nucleus with the element symbol inside.  Carbon is in the 2 nd period, so it has two energy levels, or shells.  Draw the shells around the nucleus.

30. Bohr model of the atom Element name Atomic number = number of protons = number of electrons (for now…) Element symbol Average atomic mass

31. C Bohr model of the atom  Add the electrons.  Carbon has 6 electrons.  The first shell can only hold 2 electrons.

32. C Bohr model of the atom  Since you have 2 electrons already drawn, you need to add 4 more.  These go in the 2 nd shell.  Add one at a time - starting on the right side and going counter clock-wise.

33. C Bohr model of the atom  Check your work.  You should have 6 total electrons for Carbon.  Only two electrons can fit in the 1 st shell.  The 2 nd shell can hold up to 8 electrons.  The 3 rd shell can hold 18, but the elements in the first few periods only use 8 electrons.

34. Bohr model of the atom  KC 3: The lowest allowable energy state of an atom is called its ground state.  KC 4: When an atom gains energy, it is in an excited state.  Wavelike properties of electron help relate atomic emission spectra, energy states of atoms, and atomic orbitals  KC 3: The lowest allowable energy state of an atom is called its ground state.  KC 4: When an atom gains energy, it is in an excited state.  Wavelike properties of electron help relate atomic emission spectra, energy states of atoms, and atomic orbitals

36. Bohr model of the atom  A photon is a particle of electromagnetic radiation having zero mass and carrying a quantum of energy.  When a photon strikes an atom it gives the atoms more energy. If enough photons strike an atom it may cause electrons to jump levels.  A photon is a particle of electromagnetic radiation having zero mass and carrying a quantum of energy.  When a photon strikes an atom it gives the atoms more energy. If enough photons strike an atom it may cause electrons to jump levels.

37. Bohr model of the atom  KC 5: The excited state occurs when an atom has a higher potential energy than it has at its ground state.  When an excited atom falls back to its ground state the substance will give off a unique color of light.

38. Bohr model of the atom  KC 6: The behavior of electrons is still not fully understood, but it is known that they do not move around the nucleus in circular orbits  We use Bohr’s model because it is easy to picture and gives us a basic understanding of the atom  KC 6: The behavior of electrons is still not fully understood, but it is known that they do not move around the nucleus in circular orbits  We use Bohr’s model because it is easy to picture and gives us a basic understanding of the atom

39. Whiteboard Practice  Draw the Bohr model for the following elements:  Boron  Calcium  Chlorine  Nitrogen  Draw the Bohr model for the following elements:  Boron  Calcium  Chlorine  Nitrogen

40. EQ 4: What is an atom made of? KnowWant to knowLearned

41. EQ 4: What is an atom made of?  KC 1: An atom is made of a nucleus containing protons and neutrons. Electrons move around the nucleus.

42. EQ 4: What is an atom made of?  KC 2: The number of protons and the mass number define the identity of the atom  Each element contains a unique positive charge in their nucleus  KC 2: The number of protons and the mass number define the identity of the atom  Each element contains a unique positive charge in their nucleus

43. What is an atom made of?  KC 3: The number of protons in the nucleus of an atom identifies the element and is known as the element’s atomic number

44. Atoms and Isotopes  All atoms of a particular element have the same number of protons and electrons but the number of neutrons in the nucleus can differ  KC 4: Atoms with the same number of protons but different numbers of neutrons are called isotopes  All atoms of a particular element have the same number of protons and electrons but the number of neutrons in the nucleus can differ  KC 4: Atoms with the same number of protons but different numbers of neutrons are called isotopes

47. Atomic Mass and Isotopes  The relative abundance of each isotopes is usually constant  Isotopes containing more neutrons have a greater mass  Isotopes have the same chemical behavior  KC 5: The atomic mass is the sum of the protons and neutrons in the nucleus  The relative abundance of each isotopes is usually constant  Isotopes containing more neutrons have a greater mass  Isotopes have the same chemical behavior  KC 5: The atomic mass is the sum of the protons and neutrons in the nucleus

48. Atomic Mass and Isotopes

49. Isotopes  There are 2 ways you will see isotopes written: Aluminum-27 Al  There are 2 ways you will see isotopes written: Aluminum-27 Al 27 13

50.  One atomic mass unit (amu) is defined as 1/12 th the mass of a carbon-12 atom  One amu is nearly, but not exactly, equal to one proton and one neutron.  One atomic mass unit (amu) is defined as 1/12 th the mass of a carbon-12 atom  One amu is nearly, but not exactly, equal to one proton and one neutron. Atomic Mass

51. Calculating Averages  If you are shopping, and something is $24.99 and 15% off, how much would you pay?

52. Average Atomic Mass  KC 6: The average atomic mass of an element is the weighted average mass of the isotopes of that element

53. Average Atomic Mass  Average atomic mass = (mass 1 x abundance 1 ) + (mass 2 x abundance 2 ) + … IstotopeMassAbundanceTotal Mg - 2423.9850.787018.876 Mg - 2524.9860.10132.531 Mg - 2625.9830.11172.902 Average atomic mass =24.309 amu

54. Practice Problems 1.The four isotopes of lead and its abundances are: Pb-204, 1.37%; Pb-206, 26.26%; Pb-207, 20.82%; and Pb-208, 51.55%. Calculate lead’s approximate atomic mass. IstotopeMassAbundanceTotal Pb-204 Pb-206 Pb-207 Pb-208 Average atomic mass =

55. Practice Problems 2.Calculate the average atomic mass of neon if neon exists naturally as 90.92% neon-20, 0.257% neon-21, and 8.82% neon-22. IstotopeMassAbundanceTotal Average atomic mass =

56. Practice Problems 3.Titanium has 5 common isotopes: 46 Ti (8.0%), 47 Ti (7.8%), 48 Ti (73.4%), 49 Ti (5.5%), 50 Ti (5.3%). What is the average atomic mass of titanium?

57. EQ 5: How do you determine the number of protons, neutrons, and electrons in an atom?  Atom Basics – building blocks of chemistry  These are must knows!!  Atom Basics – building blocks of chemistry  These are must knows!!

58. You must be able to answer the following questions… 1.What is my name? 2.What is my atomic number? 3.What is my average atomic mass? 4.(Pick one of my isotopes on the left side of the card). What would the atomic mass of that particular atom? 5. How many protons do I have? 6.How many neutrons do I have? 7.How many electrons do I have if I am neutral? 8.(Pick an ion of the right side of the card). How many protons and electrons do I have? 9.(Consider that I am the previous chosen isotope above and a neutral atom) What happens to me if I gain a p+_________ n o _________ e- ________ 10.What happens to me if I lose a p+_________ n o _________ e- _________ 1.What is my name? 2.What is my atomic number? 3.What is my average atomic mass? 4.(Pick one of my isotopes on the left side of the card). What would the atomic mass of that particular atom? 5. How many protons do I have? 6.How many neutrons do I have? 7.How many electrons do I have if I am neutral? 8.(Pick an ion of the right side of the card). How many protons and electrons do I have? 9.(Consider that I am the previous chosen isotope above and a neutral atom) What happens to me if I gain a p+_________ n o _________ e- ________ 10.What happens to me if I lose a p+_________ n o _________ e- _________

59. 1. What is my name?

60. 2. What is my atomic number?  KC 1: An atom’s atomic number is equal to the number of protons, which is found on the periodic table

61. 3. What is my average atomic mass?  KC 2: Average atomic mass is the averages of all of the isotopes of an element. This number is calculated and based on abundance, but also found on the periodic table.

62. 4. What is the atomic mass of a particular isotope?

63. 5. How many protons do I have?  KC 3: The number of protons is equal to the atomic number, which is found on the periodic table

64. 6. How many neutrons do I have?  KC 4: The atomic mass = protons + neutrons  Atomic number = number of protons  KC 5: neutrons = atomic mass – atomic number  KC 4: The atomic mass = protons + neutrons  Atomic number = number of protons  KC 5: neutrons = atomic mass – atomic number

65. 7. How many electrons do I have if I am neutral?  KC 6: The number of electrons is equal to the number of protons in a neutral atom

66. 8. How many protons and neutrons do I have if I am neutral?  If the atom is neutral, the protons and neutrons are found from the atomic mass and atomic number of that particular isotope  Protons = atomic number  Neutrons = atomic mass – atomic number  If the atom is neutral, the protons and neutrons are found from the atomic mass and atomic number of that particular isotope  Protons = atomic number  Neutrons = atomic mass – atomic number

67. 9. & 10. What happens if I gain/lose a p +, n 0, and e - ?  KC 7: When the number of protons changes, the identity of the element changes  KC 8: When the number of neutrons changes, the atomic mass changes  KC 9: When the number of electrons changes, the atom is no longer neutral and has a charge  KC 7: When the number of protons changes, the identity of the element changes  KC 8: When the number of neutrons changes, the atomic mass changes  KC 9: When the number of electrons changes, the atom is no longer neutral and has a charge

68. What happens if I gain/lose a p +, n 0, and e - ?  Example: Calcium – 40 p+________________ n o ________________ e- _________________  Example: Calcium – 40 p+________________ n o ________________ e- _________________

70. 1.What is my name? 2.What is my atomic number? 3.What is my average atomic mass? 4.(Pick one of my isotopes on the left side of the card). What would the atomic mass of that particular atom? 5. How many protons do I have? 6.How many neutrons do I have? 7.How many electrons do I have if I am neutral? 8.(Pick an ion of the right side of the card). How many protons and electrons do I have? 9.(Consider that I am the previous chosen isotope above and a neutral atom) What happens to me if I gain a p+_________ n o _________ e- ________ 10.What happens to me if I lose a p+_________ n o _________ e- _________