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1. Plastic, wood, and iron are all made up of. Cells Atoms Carbon plants. 2. All of the substances on the periodic table are classified as elements because they. Are pure substances. Are composed of 2 or more different types of atoms. Cannot be broken down into other substances.
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1. Plastic, wood, and iron are all made up of • Cells • Atoms • Carbon • plants
2. All of the substances on the periodic table are classified as elements because they • Are pure substances. • Are composed of 2 or more different types of atoms. • Cannot be broken down into other substances. • Cannot be dissolved in water or other liquids. 29
3. Which of the following is the basis for arranging the elements in the modern periodic table? • Alphabetical order • Masses of atoms • Number of protons • Date of discovery
4. What do elements in the same column have in common? • Similar chemical properties • Number of protons • Masses of their atoms • Size of their atoms
5. Which statement is true about the Noble gases? • The Noble gases react easily with metals. • The Noble gases share electrons with other gases. • The Noble gases are very unstable at room temperature. • The Noble gases are very stable and usually non-reactive.
6. As you move across the periodic table from right to left within a period, the elements • Become less stable. • Become more reactive. • Change from gases to solids. • Change from metals to nonmetals. 0
7. Maria measures the length of a piece of wood as 2.7 meters. What is the length of the wood in centimeters? • 0.27 • 2.7 • 270 • 2,700 28
8. Which substance can be separated into simpler substances by physical methods? • Oxygen • Water • Carbon dioxide • saltwater 25
9. A student mixes two clear liquids in a flask as directed by his teacher. A moment later a white solid forms at the bottom of the flask. What can the student conclude from this observation? • No chemical change has occurred. • A chemical change has occurred. • No new substances have formed. • A mixture has been created.
10. All methane (CH4) molecules have the same composition. What is the ratio of carbon to hydrogen atoms in a methane molecule? • 1:2 • 2:1 • 1:4 • 4:1