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2. Chapter 19: Elements and Their Properties Unit 5: Diversity of Matter Table of Contents 19 19.3: Mixed Groups 19.1: Metals 19.2: Nonmetals

36. 19.1 Section Check Question 1 What are common properties of metals? Answer Metals are good conductors of heat and electricity, reflect light, are malleable and ductile, and, except for Mercury, are solid at room temperature.

37. 19.1 Section Check Question 2 Which of these best describes electrons in metallic bonding? A. electron acceptor B. electron cloud C. electron donor D. electrons in fixed orbits

38. 19.1 Section Check Answer The answer is B. In metallic bonding, positively charged metallic ions are surrounded by a cloud of electrons.

39. 19.1 Section Check Question 3 How do alkaline earth metals differ from alkali metals?

40. 19.1 Section Check Answer Alkali metals have one electron in the outer energy level of each atom. Each atom of alkaline earth metals has two electrons in its outer energy level.

61. 19.2 Section Check Question 1 Which elements exist primarily as gases or brittle solids at room temperature? A. metals B. metalloids C. nonmetals D. synthetics

62. 19.2 Section Check Answer The answer is C. Solid nonmetals are brittle or powdery and not malleable or ductile.

63. 19.2 Section Check Question 2 A(n) __________ molecule consists of two atoms of the same element in a covalent bond. A. actinide B. allotropic C. diatomic D. lanthanide

64. 19.2 Section Check Answer The answer is C. When water is broken down into its elements, hydrogen becomes a gas made up of diatomic molecules.

65. 19.2 Section Check Question 3 Which of the following accounts for 90 percent of the atoms in the universe? A. carbon B. hydrogen C. nitrogen D. oxygen

66. 19.2 Section Check Answer The answer is B. Hydrogen makes up 90 percent of the atoms in the universe. On Earth, most hydrogen is found in the compound water.

97. 19.3 Section Check Question 1 Which of these compounds is not an allotrope of carbon? A. buckminsterfullerene B. diamond C. graphite D. quartz

98. 19.3 Section Check Answer The answer is D. Quartz is a mineral composed of silicon dioxide. Diamond Graphite Buckminsterfullerener

99. 19.3 Section Check Question 2 If you want to use a circle graph to represent the amount of hydrogen in the universe relative to other elements, how many degrees will be used to represent hydrogen? A. 36º B. 90º C. 186º D. 324º

100. 19.3 Section Check Answer The answer is D. 90 percent of the 360º in a circle is equal to 324º.

101. 19.3 Section Check Question 3 Elements having more than 92 protons are called __________. Answer The atomic number of uranium is 92. Elements having more than 92 protons are called transuranium elements, and are synthetic and unstable.

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103. End of Chapter Summary File