Which type of solid crystals will conduct heat and electricity?

Options

A. ionic crystals
B. Covalent crystal
C. metallic crystals
D. molecular crystals

Answer

To determine which type of solid crystals will conduct heat and electricity, we need to analyze the properties of different types of crystals based on their bonding and electron availability.

### Step-by-Step Solution:

1. **Understanding Conductivity**:
- Heat and electricity are conducted by the movement of free electrons. Therefore, a solid must have free electrons to conduct heat and electricity.

2. **Types of Crystals**:
- There are three main types of crystalline solids: ionic crystals, covalent crystals, molecular crystals, and metallic crystals.

3. **Ionic Crystals**:
- Ionic crystals, such as sodium chloride (NaCl), consist of ions held together by strong electrostatic forces.
- In these crystals, there are no free electrons available for conduction.
- **Conclusion**: Ionic crystals do not conduct heat and electricity.

4. **Covalent Crystals**:
- Covalent crystals are formed by atoms that share electrons to create covalent bonds.
- Since these atoms are already sharing their electrons, there are no free electrons available for conduction.
- **Conclusion**: Covalent crystals do not conduct heat and electricity.

5. **Molecular Crystals**:
- Molecular crystals consist of molecules held together by intermolecular forces.
- These crystals also lack free electrons, as the molecules do not have the ability to conduct electricity.
- **Conclusion**: Molecular crystals do not conduct heat and electricity.

6. **Metallic Crystals**:
- Metallic crystals are characterized by a lattice of metal cations surrounded by a sea of delocalized electrons (free electrons).
- These free electrons can move freely throughout the structure, allowing metallic crystals to conduct both heat and electricity effectively.
- **Conclusion**: Metallic crystals are the type of solid that can conduct heat and electricity.

### Final Answer:
The type of solid crystals that will conduct heat and electricity are **metallic crystals**.

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