In paragraph 2, what is the author's purpose in presenting the information about the decision by Meyer and Mendeleyev to leave gaps in the periodic table? A. To illustrate their confidence that the organizing principles of the periodic table would govern the occurrence of all chemical elements B. To indicate that some of their analyses of periodic physical and chemical properties were later found to be wrong C. To support the idea that they were unwilling to place new elements in the periodic table D. To indicate how they handled their disagreement about where to place new elements