question_answer 44)

  Which of the following elements will form an acidic oxide? (a) An element with atomic number 7                    (b) An element with atomic number 3 (c) An element with atomic number 12                  (d) An element with atomic number 19

Answer:

                  (a) Non-metals can form acidic oxides in general. Non-metals have 4 to 8 electrons in the outermost shell. The electronic configuration of given elements are (a) i.e., 7 = 2, 5                   (b) i.e., 3 = 2, 1                  (c) i.e., 12 = 2, 8, 2            (d) i.e., 19 = 2, 8, 8, 1. So, element with atomic number 7 (electronic configuration 2, 5) with is non-metal (N) and it will form an acidic oxide. Rest three elements atomic numbers, 3 (Li), 12 (Mg) and19 (K) are metals and hence form basic oxides.