Which of the following arrangements correctly represents hexagonal and cubic close packed structure respectively ?

Options

A. ABAB……..and ACBACB
B. ABCABC……… and ABAB
C. Both have ABCABC ……………….arrangement
D. Both have ABAB …………arrangement

Answer

To determine which arrangements correctly represent hexagonal close-packed (HCP) and cubic close-packed (CCP) structures, we need to understand the characteristics of each arrangement.

### Step-by-Step Solution:

1. **Understand the HCP Structure**:
- In the hexagonal close-packed (HCP) structure, the arrangement of spheres follows an AB-AB pattern. This means that the spheres in the third layer are directly above the spheres in the first layer.
- The layers are arranged such that the first layer (A) is followed by the second layer (B), and then the third layer (A) is positioned directly above the first layer.

2. **Understand the CCP Structure**:
- In the cubic close-packed (CCP) structure, the arrangement of spheres follows an ABC-ABC pattern. This means that the spheres in the third layer do not directly align with the spheres in the first layer.
- The layers are arranged such that the first layer (A) is followed by the second layer (B), and then the third layer (C) is positioned in such a way that it does not align directly above the first layer.

3. **Identify the Options**:
- Review the provided options to see which one correctly represents the HCP and CCP structures based on the patterns described above.

4. **Conclusion**:
- After analyzing the options, select the one that shows the AB-AB arrangement for HCP and the ABC-ABC arrangement for CCP.

### Final Answer:
- The correct option that represents the hexagonal close-packed structure (HCP) and the cubic close-packed structure (CCP) is **Option A**.