June 2013 Chemistry Regents #66-69

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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Question 51-53 Questions 54-56 Questions 57-59 Questions 60-62 Questions 63-65 Questions 66-69 Questions 70-73 Questions 74-77  Questions 78-80  Questions 81-82  Questions 83-85

 

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Base your answers to questions 66 through 69  on the information below.

 

Before atomic numbers were known, Mendeleev developed a classification system for the 63 elements known in 1872, using oxide formulas and atomic masses. He used an R in the oxide formulas to represent any element in each group. The atomic mass was listed in parentheses after the symbol of each element. A modified version of Mendeleev's classification system is shown in the table below.

66 Identify one characteristic used by Mendeleev to develop his classification system of the elements. [1]

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increasing atomic mass

atomic mass

oxide formulas

(it was in the first sentence)

67 Based on Mendeleev's oxide formula, what is the number of electrons lost by each atom of the elements in Group III? [1]

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3

68 Based on Table J , identify the least active metal listed in Group I on Mendeleev's table. [1]

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Silver or Ag

(you had to look at the bottom of table J and look at group 1 in the question)

69 Explain, in terms of chemical reactivity, why the elements in Group 18 on the modern Periodic Table were not identified by Mendeleev at that time. [1]

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Since the Group 18 elements tend not to react with other elements, there were no oxide compounds for Mendeleev to study.

Group 18 elements are generally unreactive.

on to Questions 70-73

 

 

Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Question 51-53 Questions 54-56 Questions 57-59 Questions 60-62 Questions 63-65 Questions 66-69 Questions 70-73 Questions 74-77  Questions 78-80  Questions 81-82  Questions 83-85

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