23.(a) Show the formation of Na2O by the transfer of electrons between the combining atoms. (b) Why are ionic compounds usually hard? (c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state?
Answers
Explanation:
a) A sodium atom (2, 8, 1) loses one electron to form a sodium cation. But an oxygen atom (2, 6) can become an oxide ion O2– only when it accepts 2 electrons. Thus it requires two sodium atoms to lose one electron each. In this case the doubly negative charge of oxide anion is balanced exactly by two single positively charged sodium cations. Therefore, there are two cations (Na+) to each oxygen anion (O2–) and the ratio of sodium ions to oxide ions is 2: 1. This is indicated as given below:
(b) These are relatively hard because these are present as aggregates of several positive and negative ions combined together by strong electrostatic forces.
(c) The conduction of electrictiy through a solution involves the movement of charged particles. A solution of an ionic compound in molten state contain ions thus conduct electricity, But in solid state movement of ion is not possible due to their rigid structure.
Explanation:
sodium at loses one electron but an oxygen atom gains two electrons in this case negatively charged ions are balanced exactly by two single positively charged to sodium cations to each oxygen and A ratio will be 2 is to 1