1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu How to Use This Presentation To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” To advance through the presentation, click the right-arrow key or the space bar. From the resources slide, click on any resource to see a presentation for that resource. From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. You may exit the slide show at any time by pressing the Esc key.

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter Presentation Transparencies Image and Math Focus Bank Bellringers Standardized Test Prep CNN Videos Visual Concepts Resources

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Introduction to Atoms Table of Contents Section 1 Development of the Atomic Theory Section 2 The Atom Chapter 11

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Bellringer The following is a quote by Democritus (c. 460–c. 370 bce). Paraphrase this quote in your own words in your science journal. “Color exists by convention, sweet by convention, bitter by convention; in reality nothing exists but atoms and the void.” What do you know about Democritus? And why are his thoughts important? Chapter 11

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Objectives Describe some of the experiments that led to the current atomic theory. Compare the different models of the atom. Explain how the atomic theory has changed as scientists have discovered new information about the atom. Chapter 11

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory The Beginning of the Atomic Theory What Is an Element? Around 440 BCE, a Greek philosopher named Democritus thought that you would eventually end up with a particle that could not be cut. He called this particle an atom. From Aristotle to Modern Science Aristotle, another Greek philosopher, disagreed with Democritus’s ideas. He believed that you would never end up with a particle that could not be cut. Chapter 11

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory The Beginning of the Atomic Theory, continued From Aristotle to Modern Science Democritus was right, though: Matter is made of particles, which we call atoms. An atom is the smallest particle into which an element can be divided and still be the same substance. Chapter 11

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Dalton’s Atomic Theory Based on Experiments Dalton’s Theory John Dalton published his atomic theory in 1803. His theory stated that all substances are made of atoms. Atoms are small particles that cannot be created, divided, or destroyed. Atoms of the same element are exactly alike, and atoms of different elements are different. Atoms join with other atoms to make new substances. Not Quite Correct The atomic theory was then changed to describe the atom more correctly. Chapter 11

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Thomson’s Discovery of Electrons Negatively Charged Particles Thomson experimented with a cathode-ray tube like the one shown on the next slide. He discovered negatively charged particles that are now known as electrons. Like Plums in Pudding After learning that atoms contain electrons, Thomson proposed a new model of the atom. Thomson thought that electrons were mixed throughout an atom, like plums in a pudding. Chapter 11

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Chapter 11

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Rutherford’s Atomic “Shooting Gallery” Negatively Charged Particles In 1909, Ernest Rutherford aimed a beam of small, positively charged particles at a thin sheet of gold foil. The next slide shows his experiment. Surprising Results Rutherford expected the particles to pass right through the gold in a straight line. To Rutherford’s great surprise, some of the particles were deflected. Chapter 11

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Chapter 11

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Where Are the Electrons? Far from the Nucleus Rutherford proposed that in the center of the atom is a tiny, positively charged part called the nucleus. Bohr’s Electron Levels In 1913, Niels Bohr proposed that electrons move around the nucleus in certain paths, or energy levels. Chapter 11

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Where Are the Electrons?, continued The Modern Atomic Theory According to the current theory, there are regions inside the atom where electrons are likely to found. These regions are called electron clouds. Chapter 11

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Chapter 11 Comparing Models of the Atom Click below to watch the Visual Concept. You may stop the video at any time by pressing the Esc key. Visual Concept

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Bellringer Answer the following question: An atom is the smallest particle into which an element can be divided and still be that element. Now that scientists have learned that an atom is made up of even smaller particles, is this definition still accurate? Explain your answer in your science journal. Chapter 11

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Objectives Describe the size of an atom. Name the parts of an atom. Describe the relationship between numbers of protons and neutrons and atomic number. Chapter 11

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Objectives, continued State how isotopes differ. Calculate atomic masses. Describe the forces within an atom. Chapter 11

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom How Small Is an Atom? Three One-Hundred-Millionths of a Centimeter! Scientists know that aluminum is made of average- sized atoms. An aluminum atom has a diameter of about 0.00000003 cm. Chapter 11

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom What Is an Atom Made Of? The Nucleus Protons are positively charged particles in the nucleus. Neutrons are the particles of the nucleus that have no electrical charge. Outside the Nucleus Electrons are the negatively charged particles in atoms. Electrons are found around the nucleus within electron clouds. All the structures of the atom can be seen on the next slide. Chapter 11

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Chapter 11

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom How Do Atoms of Different Elements Differ? Starting Simply The hydrogen atom has one proton and one electron. Now for Some Neutrons The helium atom has two protons, two neutrons, and two electrons. Chapter 11

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom How Do Atoms of Different Elements Differ? Building Bigger Atoms For bigger atoms, simply add protons, neutrons, and electrons. Protons and Atomic Number The number of protons in the nucleus of an atom is the atomic number of that atom. All atoms of an element have the same atomic number. Chapter 11

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Isotopes Isotopes are atoms that have the same number of protons but have different numbers of neutrons. Chapter 11

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Isotopes, continued Properties of Isotopes An unstable atom is an atom with a nucleus that will change over time. This type of isotope is radioactive. Telling Isotopes Apart You can identify each isotope of an element by its mass number. The mass number is the sum of the protons and neutrons in an atom. Chapter 11

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Isotopes, continued Chapter 11

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Isotopes, continued Naming Isotopes To identify a specific isotope of an element, write the name of the element followed by a hyphen and the mass number of the isotope. Calculating the Mass of an Element The atomic mass of an element is the weighted average of the masses of all the naturally occurring isotopes of that element. Chapter 11

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Chapter 11

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Forces in Atoms Four Basic Forces Four basic forces are at work everywhere, even within the atom. These forces are gravitational force, electromagnetic force, strong force, and weak force. These forces work together to give an atom its structure and properties. Chapter 11

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Chapter 11

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Introduction to Atoms Use the terms below to complete the concept map on the next slide. Chapter 11 Concept Map a nucleus mass number isotopes protons atoms electrons atomic number

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concept Map Chapter 11

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concept Map Chapter 11

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu End of Chapter 11 Show

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Read each of the passages. Then, answer the questions that follow each passage. Chapter 11 Reading

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 Passage 1 In the Bohr model of the atom, electrons can be found only in certain energy levels. Electrons “jump” from one level to the next level without passing through any of the regions in between. When an electron moves from one level to another, it gains or loses energy, depending on the direction of its jump. Bohr’s model explained an unusual event. When electric charges pass through atoms of a gaseous element, the gas produces a glowing light, like in a neon sign. Continued on the next slide

37. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 Passage 1, continued If this light is passed through a prism, a pattern of lines appears, each line having a different color. The pattern depends on the element—neon has one pattern, and helium has another. In Bohr’s model, the lines are caused by electron jumps from higher to lower energy levels. Because only certain jumps are possible, electrons release energy only in certain quantities. These “packets” of energy produce the lines that are seen.

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. In the Bohr model of the atom, what limitation is placed on electrons? A the number of electrons in an atom B the electrons’ being found only in certain energy levels C the size of electrons D the speed of electrons

39. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. In the Bohr model of the atom, what limitation is placed on electrons? A the number of electrons in an atom B the electrons’ being found only in certain energy levels C the size of electrons D the speed of electrons

40. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. What causes the colored lines that appear when the light from a gas is passed through a prism? F packets of energy released by electron jumps G electrons changing color H atoms of the gas exchanging electrons I There is not enough information to determine the answer.

41. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. What causes the colored lines that appear when the light from a gas is passed through a prism? F packets of energy released by electron jumps G electrons changing color H atoms of the gas exchanging electrons I There is not enough information to determine the answer.

42. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 Passage 2 No one has ever seen a living dinosaur, but scientists have determined the appearance of Tyrannosaurus rex by studying fossilized skeletons. Scientists theorize that these extinct creatures had big hind legs, small front legs, a long, whip-like tail, and a mouth full of dagger-shaped teeth. However, theories of how T. rex walked have been harder to develop. For many years, most scientists thought that T. rex plodded slowly like a big, lazy lizard. Continued on the next slide

43. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 Passage 2, continued However, after studying well- preserved dinosaur tracks and noticing skeletal similarities between certain dinosaur fossils and living creatures like the ostrich, many scientists now theorize that T. rex could turn on the speed. Some scientists estimate that T. rex had bursts of speed of 32 km/h (20 mi/h)!

44. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. According to this passage, where does most of what we know about the appearance of Tyrannosaurus rex come from? A fossilized skeletons B dinosaur tracks C living organisms such as the ostrich D living specimens of T. rex

45. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. According to this passage, where does most of what we know about the appearance of Tyrannosaurus rex come from? A fossilized skeletons B dinosaur tracks C living organisms such as the ostrich D living specimens of T. rex

46. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. How did scientists conclude that T. rex could probably move very quickly? F They measured the speed at which it could run. G They compared fossilized T. rex tracks with T. rex skeletons. H They studied dinosaur tracks and noted similarities between ostrich skeletons and T. rex skeletons. I They measured the speed at which ostriches could run.

47. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. How did scientists conclude that T. rex could probably move very quickly? F They measured the speed at which it could run. G They compared fossilized T. rex tracks with T. rex skeletons. H They studied dinosaur tracks and noted similarities between ostrich skeletons and T. rex skeletons. I They measured the speed at which ostriches could run.

48. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Use the diagram of an atom below to answer the questions that follow. Chapter 11 Interpreting Graphics

49. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. The black circles in the center of the model represent neutrons. What do the white circles in the center represent? A electrons B protons C nuclei D atoms

50. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. The black circles in the center of the model represent neutrons. What do the white circles in the center represent? A electrons B protons C nuclei D atoms

51. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. What is the mass number of the atom shown in the model? F 3 G 7 H 9 I 11

52. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. What is the mass number of the atom shown in the model? F 3 G 7 H 9 I 11

53. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 3. What is the overall charge of the atom shown in the model? A 12 B 11 C 0 D 21

54. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 3. What is the overall charge of the atom shown in the model? A 12 B 11 C 0 D 21

55. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Read each question, and choose the best answer. Chapter 11 Math

56. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. Aimee, Mari, and Brooke are 163 cm, 171 cm, and 175 cm tall. Which of the following measurements is a reasonable average height of these three friends? A 170 cm B 175 cm C 255 cm D 509 cm

57. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 1. Aimee, Mari, and Brooke are 163 cm, 171 cm, and 175 cm tall. Which of the following measurements is a reasonable average height of these three friends? A 170 cm B 175 cm C 255 cm D 509 cm

58. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. A certain school has 40 classrooms. Most of the classrooms have 25 to 30 students. Which of the following is a reasonable estimate of the number of students that go to this school? F 40 students G 100 students H 1,100 students I 2,000 students

59. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 2. A certain school has 40 classrooms. Most of the classrooms have 25 to 30 students. Which of the following is a reasonable estimate of the number of students that go to this school? F 40 students G 100 students H 1,100 students I 2,000 students

60. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 3. Jenna is setting up a fish tank in her room. The tank is the shape of a rectangular prism. The height of the tank is 38 cm, the width is 23 cm, and the length is 62 cm. The tank is filled with water to a point that is 7 cm from the top. How much water is in the tank? A 44,206 cm 3 B 48,070 cm 3 C 54,188 cm 3 D 64,170 cm 3

61. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 3. Jenna is setting up a fish tank in her room. The tank is the shape of a rectangular prism. The height of the tank is 38 cm, the width is 23 cm, and the length is 62 cm. The tank is filled with water to a point that is 7 cm from the top. How much water is in the tank? A 44,206 cm 3 B 48,070 cm 3 C 54,188 cm 3 D 64,170 cm 3

62. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 4. Which of the following is equal to 8 5 ? F 8  8  8  8  8 G 5  5  5  5  5  5  5  5 H 5  8 I 8  8  8  8  8

63. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11 4. Which of the following is equal to 8 5 ? F 8  8  8  8  8 G 5  5  5  5  5  5  5  5 H 5  8 I 8  8  8  8  8

64. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Chapter 11

65. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Development of the Atomic Theory Chapter 11

66. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Chapter 11

67. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Chapter 11

68. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Chapter 11

69. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Preparation Chapter 11

70. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 The Atom Chapter 11