Name: Period: ELEMENTS AND ATOMS Chapter 1. The Building Blocks of matter pages L6-11

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1 Name: Period: ELEMENTS AND ATOMS Chapter 1 The Building Blocks of matter pages L The simplest pure substances are called. 2. Why are elements often called the building blocks of matter? 3. Is the following sentence true or false? Sodium chloride is an example of a compound. 4. Circle the letter of each choice that is an example of a mixture. A. Air B. Soil C. Gasoline D. Oxygen 5. The smallest particle of an element is a(n). Atomic Theory and Models 6. Why do scientists use models to help them understand atoms? 7. Circle the letter of each sentence that is part of John Dalton s atomic theory. A. All elements are composed of atoms. B. No two atoms of the same element are exactly alike. C. An atom of one element cannot be changed into an atom of a different element. D. Atoms cannot be created or destroyed in any chemical changes. 8. Is the following sentence true or false? With only a few changes, Dalton s atomic theory is still accepted today.. 9. Who described the atom as negative charges scattered through a ball of positive charge?. 10. What experiment convinced Ernest Rutherford that the atom has a small, positively charged nucleus?. 11. The term Rutherford gave to the positively charged particles in the nucleus of an atom was. 12. The atomic model of resembled planets orbiting the sun. 13. A region around the nucleus in which electrons of the same energy are likely to be found is called a(n). 14. What particle did Chadwick discover in 1932 that was hard to detect because it has no electrical charge?. 15. Is the following sentence true or false? Since the 1930 s, the model of the atom has changed a great deal Circle the letter of each sentence that we now know to be true about atoms. A. Most of the mass of atoms is due to electrons. B. Atoms have no overall electrical charge. C. Atoms of different elements have the same number of protons. D. Most of the volume of atoms consists of protons and neutrons. Label each model of the atom with the name of the scientist who developed it

2 Match each term with its definition by writing the letter of the correct definition on the line beside the term in the left column. 21. matter 22. element 23. compound 24. mixture 25. atom A. Two or more substances that are in the same place but not chemically combined. B. negatively charged particle in an atom C. well-tested idea that explains and connects a wide range of observations D. anything that has mass and takes up space E. smallest particle of an element 26. scientific theory F. positively charged region in the center of an atom 27. model G. pure substance made of two or more elements that are combine chemically in a specific ratio. 28. electron H. positively charged particle in the nucleus of an atom 29. nucleus I. physical or other representation of an idea to help people understand what they cannot observe directly 30. proton J. simplest pure substance that cannot be broken down into any other substance Atoms, bonding, and the Periodic Table page L12-L20 Valence electrons and bonding 31. are those electrons that are held most loosely in an atom. 32. Is the following sentence true or false? The number of valence electrons in an atom of an element determines the ways in which the atom can bond Circle the letter of each sentence that is true about valence electrons and chemical bonding. A. Most atoms are less stable when they have eight valence electrons. B. Atoms whit eight valence electrons easily form compounds. C. Having eight valence electrons makes atoms very reactive. D. Atoms with eight valence electrons are less likely to form chemical bonds than atoms with fewer valence electrons. 34. Is the following sentence true or false? When atoms bond, new substances are formed. The Periodic Table 35. Each element is represented in the periodic table by a(n). 36. The of an element is the number of protons in the nucleus of an atom. 37. What is a row of elements across the periodic table called? 38. Describe how atomic number changes across a period of elements. 39. What are elements in the same column of the periodic table called? 40. Elements within a group always have the same number of. 41. Complete the table about groups of elements in the periodic table. Group number Group Name Number of Valence Electrons 1 a. 1 b. 17 c. 7 d. 18 e. 8 f. 42. How many valence electrons do all nonmetals have? Reactivity (High/Low) 43. How do metalloids differ from metals? 44. Is the following sentence true or false? Hydrogen is considered to be a metal.

3 Ionic Bonds pages L22-L An atom or group of atoms that has an electric charge is called a(n). 46. What happens to an atom when it loses an electron? 47. What happens to an atom when it gains an electron? 48. Ions that are made of more than one atom are called. 49. Use the table in the textbook to complete the table below. Ions and their Charges Name Charge Symbol or Formula Sodium a. b. Magnesium c. d. Chloride e. f. Sulfate g. h. 50. What kinds of ions do a sodium atom and a chlorine atom become when a valence electron is transferred from one to the other. 51. What is an ionic bond? 52. Give an example from the table above of two ions that can form an ionic bond. 53. A(n) is a combination of symbols that shows the ratio of elements in a compound. 54. Is the following sentence true or false? When ionic compounds form, the ions come together in a way that balances out the charges on the ions. 55. In the chemical formula for magnesium chloride (MgCl 2 ), what is the number 2 called, and what does it tell you? 56. Is the following sentence true or false? For an ionic compound, the name of the negative ion comes first when does the end of a name of a negative ion end in ide Properties of Ionic Compounds (pages L26-L27) 58. What are three characteristic properties of ionic compounds? a. b. c. 59. An orderly, three-dimensional arrangement formed by ions is called a(n) 60. In an ionic compound, which ions are attracted to each other? 61. Why do ionic compounds have high melting points?

4 62. At room temperature, ionic bonds are strong enough to cause all ionic compounds to be. 63. Why do ionic compounds conduct electricity well when they are dissolved in water? Covalent Bonds (pages 30-35) 64. What is a covalent bond? 65. The two bonded fluorine atoms form a neutral particle called a(n) 66. When two atoms share two pairs of electrons, a(n) is formed 67. Is the following sentence true or false? Atoms of some elements can share three pairs of electrons.. Molecular Compounds 68. How are atoms arranged in molecular compounds? 69. Circle the letter of each sentence that is true about molecular compounds A. More heat is needed to separate their molecules than is needed to separate ions. B. They melt at much higher temperatures that do ionic compounds. C. They boil at much higher temperatures that do ionic compounds. D. Most are poor conductors of electricity when dissolved in water. Unequal sharing of Electrons 70. How do molecules in certain molecular compounds come to have a slight electrical charge? 71. In a(n) covalent bond, electrons are shared unequally. 72. How are electrons shared in a nonpolar covalent bond? 73. How can a molecule be nonpolar overall and still contain polar bonds? 74. Is the following sentence true or false? Water molecules are polar. 75. Why do polar and nonpolar molecules have different properties? 76. Why don t water and vegetable oil mix? 77. When you do laundry, what causes nonpolar oil or greasy dirt to mix with the polar water?

5 Bonding in Metals (pages L36-L39) 78. Circle the letter of each sentence that is true about metals and metallic bonding. A. Atoms of most metals have one, two or three valence electrons. B. Metal atoms usually gain valence electrons when they combine chemically with other atoms. C. In chemical reactions, metal atoms usually become positively charged ions. D. Atoms of metals lose electrons easily. 79. What does a metal crystal consist of? 80. A(n) is a material made of two or more elements that has the properties of metal. 81. List four properties of metals 82. What explains the properties of metals? 84. Complete the table about the ability of metals to change shape. Type of Ability Definition Example Ductility a. Wire b. Ability to be rolled into thin sheets Aluminum foil 85. Is the following sentence true or false? A metals luster is due to its valence electrons Why do metals conduct electricity easily?