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8th Grade Chapter 3 Study Guide Modified True/False Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true. ____ 1. When a substance burns, matter is destroyed. _________________________ ____ 2. Elements on the far right of the periodic table are classified as nonmetals. _________________________ ____ 3. Thompson's experiments led to the discovery of the neutron. _________________________ ____ 4. The closer an electron is to the nucleus, the lower its energy. _________________________ ____ 5. Every atom of the same element has the same atomic number. _________________________ ____ 6. For an atom to be neutral, the number of protons must equal the number of neutrons. _________________________ ____ 7. Matter always has mass. _________________________ ____ 8. Pure substances are either elements or mixtures. _________________________ Multiple Choice Identify the choice that best completes the statement or answers the question. ____ ____ ____ ____ ____ ____ ____ ____ 9. Matter that has the same composition and properties throughout is called a(n) ____. A. pure substance C. atom B. mixture D. isotope 10. When two pure substances are combined so that each of the pure substances retains its own properties, the result is a(n) ____. A. compound C. element B. mixture D. isotope 11. All ____ except mercury are solids at room temperature. A. metalloids C. metals B. nonmetals D. mixtures 12. How many atoms of calcium are in a unit of calcium phosphate whose formula is Ca3(PO4)2? A. one C. three B. two D. four 13. In general, nonmetals are ____. A. good conductors of electricity C. good conductors of heat B. malleable and ductile D. gases at room temperature 14. In general, metals are ____. A. poor conductors of heat C. poor conductors of electricity B. brittle D. good conductors of heat 15. When Rutherford performed his metal foil experiment, he was surprised that most of the alpha particles ____. A. were deflected by the foil C. were absorbed by the foil B. bounced back from the foil D. passed straight through the foil 16. Which of these statements about matter is NOT true? A. During chemical changes, matter is destroyed. B. Matter has mass and takes up space. C. Matter can be divided into pure substances and mixtures. ____ 17. ____ 18. ____ 19. ____ 20. ____ 21. ____ 22. ____ 23. D. Matter is made up of atoms. The millions of compounds that exist are made from approximately ____ elements. A. 50 C. 118 B. 75 D. 150 Most of the mass of an atom is found in its ____. A. nucleus C. atomic number B. electron cloud D. mass number Vegetable soup is an example of a ____. A. homogeneous mixture C. compound B. heterogeneous mixture D. pure substance When someone stirs cocoa powder into hot water or hot milk, the cocoa changes from a ____. A. homogeneous mixture into a compound B. homogeneous mixture into a non-uniform mixture C. compound into a heterogeneous mixture D. heterogeneous mixture into a homogeneous mixture A certain atom has 26 protons, 26 electrons, and 30 neutrons. It mass number is ____. A. 26 C. 52 B. 30 D. 56 Which of the following CANNOT be classified as matter? A. an odorless, colorless gas C. alpha particles B. the heat given off by a light bulb D. an electron cloud ____ has mass and takes up space. A. Thought C. Air B. Light D. Emotion Matching Match the drawings in Figure 3-1 to the descriptions below. Figure 3-1 ____ ____ ____ ____ ____ 24. 25. 26. 27. 28. element mixture of two elements compound mixture of two compounds mixture of a compound and element Match each symbol or formula with the correct element or compound. A. O2 C. CO B. CO2 D. C ____ ____ ____ ____ 29. 30. 31. 32. carbon oxygen carbon monoxide carbon dioxide Short Answer 33. Except during World War II when steel pennies were made, pennies minted before 1984 were made entirely of copper. Pennies made later have a core of zinc covered by a thin layer of copper. Nickels contain about 25% copper and 75% nickel. Classify each type of coin in terms of elements, compounds, homogeneous mixtures, and heterogeneous mixtures. 34. Give four examples of properties of nonmetals that are exactly the opposite of properties of metals. 35. What did Rutherford expect to happen when he bombarded metal foil with alpha particles? How did his results change the model of the atom? 36. Use the periodic table to complete the data in Table 3-1. Properties of Selected Elements Symbol Name Atomic number Average Atomic Mass Fluorine O 15 S 32.066 Table 3-1