Naturally occurring copper consists of copper-63 (62.9296 amu), and copper-65 (64.9278 amu). Using the relative atomic mass from the periodic table, which of the following is the best estimate of the percent abundance of the two isotopes of copper?
A)50% copper-63 and 50% copper-65D)90% copper-63 and 10% copper-65
B)75% copper-63 and 25% copper-65E)10% copper-63 and 90% copper-65
C)25% copper-63 and 75% copper-65
52. Boron has two isotopes: B-10 and B-11, with masses of 10.013 amu and 11.009 amu, respectively. The relative atomic mass of boron is 10.81 amu. Which statement best describes the percent abundance of the isotopes of boron?
A)It contains more B-10 than B-11.
B)It contains more B-11 than B-10.
C)It contains equal amounts of B-10 and B-11.
D)There must be a third isotope of boron.
E)A mass spectrum of boron is necessary to answer this question.
53. Which of the following statements about Mendeleev's periodic table is incorrect?
A)Mendeleev arranged the known elements in order of increasing relative atomic mass.
B)He grouped elements with similar properties into columns and rows so that their properties varied in a regular pattern.
C)He arranged the elements so that they were in increasing atomic number order.
D)He was able to predict the existence and properties of several elements that were unknown at the time.
E)Mendeleev developed his table before the discovery of protons.
54. Which of the following statements about the modern periodic table in your text is incorrect?
A)The periodic table is arranged by increasing atomic mass.
B)The elements are arranged in rows and columns to emphasize periodic properties.
C)Elements in the same vertical column are called groups or families.
D)Each group has a Roman numeral and a letter associated with it.
E)A horizontal row of elements is called a period.
55. A horizontal row of elements in the periodic table is called a:
A)group.D)both group and family are correct.
B)family.E)both group and period are correct.
56. A vertical column in the periodic table is called a:
A) family or group. B) column. C) cohort. D) period. E) covey.
57. Which of the following terms does not apply to the major categories of elements in the periodic table?
B)antimetalsE)both antimetals and metalloids
58. Which of the following statements does not apply to metalloids?
A)The physical properties of metalloids resemble those of a metal.
B)All metalloids are electrical insulators.
C)Metalloids lie along the stair-step line beginning at boron.
D)The chemical properties of metalloids are similar to nonmetals.
E)Metalloids are also known as semi-metals.
59. Which of the following does not apply to the main-group elements?
A)Main-group elements are also known as representative elements.
B)Main-group elements are in groups labeled with the letter A.
C)Main-group elements are in groups labeled with the letter B.
D)Main-group elements include metals.
E)Main-group elements include nonmetals.
60. Sodium reacts vigorously with water to form hydrogen gas and a compound containing sodium ions. Which other element is expected to react with water in a similar way?
A) hydrogen B) aluminum C) nitrogen D) potassium E) silicon
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