Consider the following assumptions made while developing the ionic packing theory: 1. Cations and anions are spherical but these spheres are not hard 2. Cations are always smaller than anions 3. Each cation would tend to be surrounded by the maximum number of anions permitted by the geometry 4. Cations and anions do not touch each other  Which of the above assumptions are correct?

Consider the following assumptions made while developing the ionic packing theory: 1. Cations and anions are spherical but these spheres are not hard 2. Cations are always smaller than anions 3. Each cation would tend to be surrounded by the maximum number of anions permitted by the geometry 4. Cations and anions do not touch each other  Which of the above assumptions are correct? Correct Answer 2 and 3

  • In an ionic solid, the ions are packed together into a repeating array called a crystal lattice.
  • The concept of crystal packing assumes that the ions are hard spheres. (Statement 1 is incorrect)
  • The easiest way to picture such an array is to arrange one layer of spheres and then place successive layers over it.
  • In most ionic compounds, the anions are much larger than the cations, and it is the anions which form the crystal array. The smaller cations reside in the holes between the anions. (Statement 2 is correct)
  • Ions try to surround themselves with as many ions of opposite charge as closely as possible. Usually, in the packing arrangement, the cation is just large enough to allow the anions to surround it without touching one another. (Statement 3 is correct)
  • In ionic crystals, ions of opposite charge touch each other but ions of the same charge should not touch. (Statement 4 is incorrect)

Related Questions

Which of the following statements are true about anions and cations? Statement 1: In anions, the electrons are more than the protons. Statement 2: In cations, the electrons are less than the protons.
In an ionic crystal if the valancies of cation and anion are VC and VA and the coordination numbers of cation and anions are Nc and NA respectively, then the necessary condition for obtaining a stable crystal structure is
Read the passage carefully and choose the best answer to each question out of the four alternatives.
Doing an internship at the University of Lille in France, I almost always found myself stuck whenever I had to speak to non-Indians about India or on anything'Indian'. This was more because of the subtle differences in the way the French understood India in comparison to what I thought was 'Indian'. For instance, when I,or any Indian for that matter, say 'Hindi' is an Indian language, what it means is that it is one of the languages widely spoken in India. This need not be similar tothe understanding that the French would have when they hear of 'Hindi' as an Indian language. Because for them Hindi then becomes the only language spoken inIndia. This is a natural inference that the French, Germans, Italians and many other European nationals would tend to make, because that is generally how it is intheir own respective countries. The risk of such inappropriate generalisations made about 'Indian' is not restricted to language alone but also for India's landscape,cuisine, movies, music, climate, economic development and even political ideologies. The magnitude of diversity of one European country can be easily compared tothat of one of the Indian State, isn't it? Can they imagine that India is one country whose diversity can be equated to that of the entire European continent? Theonus is upon us to go ahead and clarify the nuances in 'Indianness' while we converse. But why should one do so? How does it even matter to clarify? The writer was working at a university in which country?