The cations and anions are arranged n alternate form in:

Options

A. Metallic crystal
B. Ionic crystal
C. C-valent crystal
D. Semi-conductor crystal

Answer

To solve the question, "The cations and anions are arranged in alternate form in:", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Types of Crystals**:
- We need to analyze the four options provided: metallic crystal, ionic crystal, covalent crystal, and semiconductor crystal.

2. **Analyzing Metallic Crystals**:
- In metallic crystals, metal cations are surrounded by a sea of delocalized electrons. The arrangement is not alternating between cations and anions.

3. **Analyzing Ionic Crystals**:
- Ionic crystals consist of cations and anions that are arranged in a repeating pattern. The cations and anions alternate in the crystal lattice, which maximizes the attraction between oppositely charged ions.

4. **Analyzing Covalent Crystals**:
- Covalent crystals are formed by atoms connected by covalent bonds. They do not have a structure where cations and anions alternate.

5. **Analyzing Semiconductor Crystals**:
- Semiconductor crystals can have various structures, but they do not specifically feature an alternating arrangement of cations and anions.

6. **Conclusion**:
- Based on the analysis, the only type of crystal where cations and anions are arranged in an alternating form is the **ionic crystal**.

### Final Answer:
The cations and anions are arranged in alternate form in **ionic crystals**.

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