By X-ray studies, the packing atoms, in a crystal of gold is found to be in layers such that starting from any layer, every fourth layer is found to be exactly idenctical. The density of gold is found to be ` 19.4 g cm^(-3)` and its atomic mass is 197 a.m.u.
The fraction occupied by gold atoms in the crystal is

Options

A. 0.52
B. 0.68
C. 0.74
D. `1.0`

Explanation

To find the fraction occupied by gold atoms in the crystal, we can follow these steps:

### Step 1: Understanding the Crystal Structure
The problem states that the packing of atoms in the gold crystal is such that every fourth layer is identical. This indicates a cubic close packing (CCP) arrangement, which is also known as face-centered cubic (FCC) structure. In this structure, the atoms are packed in a way that maximizes the density.

**Hint:** Identify the type of crystal structure based on the given information about the layers.

### Step 2: Coordination Number
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