Aluminium crystallizes in a cubic close packed structure. Its metallic radius is 125pm. The unitcells per cc of aluminium respect ivley are

Options

A. 354 pm, `2.25xx10^(22)`
B. 648pm, `3.3xx10^(23)`
C. 298 pm. `1.25xx10^(22)`
D. `436"pm", 6.3xx10^(22)`

Explanation

To solve the problem of calculating the number of unit cells per cubic centimeter (cc) of aluminum, which crystallizes in a cubic close-packed (CCP) structure, follow these steps:

### Step 1: Understand the relationship between radius and edge length in FCC structure
In a face-centered cubic (FCC) structure, the relationship between the metallic radius (r) and the edge length (a) is given by:
\[ r = \frac{a}{2\sqrt{2}} \]
This can be rearranged to find the edge length:
\[ a = 2r\sqrt{2} \]

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