To arrange the compounds in decreasing order of ionic character and assign them ranks accordingly, consider the following compounds:
1. CsCl
2. NaCl
3. SCl4
4. SiCl4
The ionic character of a compound depends on the difference in electronegativity between the cation and the anion. The greater the difference, the more ionic the character of the bond.
1. CsCl (Cesium Chloride)
- Cs (Cesium) has a very low electronegativity, and Cl (Chlorine) has a high electronegativity.
- The large difference in electronegativity between Cs and Cl results in a highly ionic bond.
- Therefore, CsCl has the highest ionic character.
2. NaCl (Sodium Chloride)
- Na (Sodium) also has a low electronegativity, though not as low as Cs.
- Cl (Chlorine) remains constant with high electronegativity.
- The difference in electronegativity between Na and Cl is still substantial, leading to a highly ionic bond, though slightly less than CsCl.
- Thus, NaCl has the second highest ionic character.
3. SCl4 (Sulfur Tetrachloride)
- S (Sulfur) has a moderate electronegativity, and Cl (Chlorine) has a high electronegativity.
- The difference in electronegativity between S and Cl is smaller compared to the previous two compounds.
- SCl4 is more covalent in nature but still has some ionic character.
- Therefore, SCl4 gets third place in terms of ionic character.
4. SiCl4 (Silicon Tetrachloride)
- Si (Silicon) has a slightly lower electronegativity compared to S but still greater than metals like Na and Cs.
- Cl (Chlorine) remains constant with high electronegativity.
- The difference in electronegativity between Si and Cl results in a bond that is comparatively less ionic and more covalent than the others listed.
- Thus, SiCl4 has the lowest ionic character among the given compounds.
Based on this reasoning, the order of compounds from the most to the least ionic character is:
1. CsCl
2. NaCl
3. SCl4
4. SiCl4
