Among the following statements, choose the correct statements, A. In Ionic solid, ions are the constituent particles. B. Ionic solids are soft. C. Ionic solid are electrical insulators in the solid state. D. Ionic solid conduct electricity in molten state. E. Ionic solid have low melting and boiling points. Choose the correct answer from the options given below:
Understanding the Properties of Ionic Solids
Let's carefully examine each statement regarding ionic solids to determine their correctness. Ionic solids are a type of chemical solid formed by the electrostatic attraction between positive ions (cations) and negative ions (anions).
Analyzing Each Statement on Ionic Solids
Statement A: In Ionic solid, ions are the constituent particles.
- This statement is correct. Ionic solids are indeed composed of ions (cations and anions) arranged in a regular, repeating three-dimensional structure called a crystal lattice. These ions are held together by strong electrostatic forces of attraction.
Statement B: Ionic solids are soft.
- This statement is incorrect. Ionic solids are typically hard. The strong electrostatic forces between the oppositely charged ions hold the crystal lattice together very rigidly, making them hard. However, they are also brittle, meaning they shatter when a force is applied that causes layers of ions with like charges to come into contact, resulting in repulsion.
Statement C: Ionic solid are electrical insulators in the solid state.
- This statement is correct. In the solid state, the ions are fixed in their positions within the crystal lattice. They are not free to move and carry electric charge. Therefore, solid ionic compounds do not conduct electricity.
Statement D: Ionic solid conduct electricity in molten state.
- This statement is correct. When an ionic solid melts, the ions become mobile and are free to move throughout the liquid. These mobile ions (both cations and anions) can carry electric charge, allowing the molten ionic compound to conduct electricity. The same applies when ionic compounds are dissolved in water; the separated and mobile ions in solution conduct electricity.
Statement E: Ionic solid have low melting and boiling points.
- This statement is incorrect. Ionic solids have high melting and boiling points. This is because a large amount of energy is required to overcome the strong electrostatic forces of attraction between the ions in the crystal lattice and break it down into a liquid or gaseous state.
Identifying the Correct Statements
Based on the analysis:
- Statement A is correct.
- Statement B is incorrect.
- Statement C is correct.
- Statement D is correct.
- Statement E is incorrect.
The correct statements are A, C, and D.
Summary of Ionic Solid Properties
| Property | Description |
|---|---|
| Constituent Particles | Ions (Cations and Anions) |
| Hardness/Brittleness | Hard but brittle |
| Melting/Boiling Points | High |
| Electrical Conductivity (Solid) | Insulator (Poor conductor) |
| Electrical Conductivity (Molten/Aqueous) | Conductor |
The option that lists A, C, and D as the correct statements is the answer.
Revision Table: Key Properties of Ionic Solids
| Property | Characteristic of Ionic Solids | Explanation |
|---|---|---|
| Building Blocks | Ions | Formed by electrostatic attraction between oppositely charged ions. |
| Structure | Crystal Lattice | Ions arranged in a regular, repeating 3D pattern. |
| Hardness | Hard | Strong electrostatic forces hold ions rigidly. |
| Brittleness | Brittle | Repulsion between like charges when layers shift. |
| Melting/Boiling Points | High | Requires significant energy to overcome strong interionic forces. |
| Electrical Conductivity (Solid) | Poor (Insulator) | Ions are fixed in the lattice, no mobile charge carriers. |
| Electrical Conductivity (Molten/Aqueous) | Good (Conductor) | Ions become mobile and can carry charge. |
Additional Information: Ionic Bonding and Crystal Structure
Ionic bonding occurs when there is a complete transfer of valence electrons from a metal atom (which becomes a cation) to a non-metal atom (which becomes an anion). This transfer creates oppositely charged ions. These ions then attract each other via strong electrostatic forces, forming the ionic bond.
The collection of these ions arranges itself into a crystal lattice structure to maximize attractive forces and minimize repulsive forces. The specific arrangement in the lattice depends on the size and charge of the ions involved. Common lattice types include face-centered cubic (FCC) like the rock salt structure (e.g., NaCl) and body-centered cubic (BCC) like the cesium chloride structure (e.g., CsCl).
The strength of the ionic bond is influenced by factors like the magnitude of the charges on the ions (higher charges lead to stronger attraction) and the distance between the ions (smaller distance leads to stronger attraction). These factors contribute to the characteristic properties of ionic solids, such as their high melting points and hardness.
Important Questions from Crystalline Solid
How many anions surround a sodium ion in a crystal lattice of sodium chloride?
Atoms of element B form hcp lattice and those of the element A occupy 2/3 rd of tetrahedral voids. What is the formula of the compound formed by the elements A and B?
Which of the following statements best describes the characteristics of a crystalline solid?
