Given an alloy of Cu, Ag and Au in which Cu atoms constitute the ccp arrangement . If the hypothetical formula of the alloy is `Cu_4 Ag_3 Au` , the probable locations of Ag and Au atoms are

Options

A. Ag- all tetrahedral voids , Au - all octahedral voids
B. Ag- (3th)/8 tetrahedral voicks , Au - (1th)/4 octahedral voids
C. Ag- 1/2 octahedral voicks , Au - 1/2 tetrahedral voids
D. Ag- all octahedral voicks , Au - all tetrahedral voids

Answer

To solve the problem regarding the locations of Ag and Au atoms in the alloy with the formula Cu₄Ag₃Au, we need to analyze the arrangement of the copper atoms and the voids available for the silver (Ag) and gold (Au) atoms.

### Step-by-Step Solution:

1. **Understanding the Arrangement**:
- Copper (Cu) atoms are arranged in a cubic close-packed (CCP) structure. In this arrangement, there are two types of voids: tetrahedral and octahedral.

2. **Identifying the Number of Voids**:
- In a CCP structure, for every atom, there are:
- 8 tetrahedral voids.
- 4 octahedral voids.

3. **Analyzing the Alloy Composition**:
- The given formula is Cu₄Ag₃Au. This means:
- There are 4 copper atoms.
- There are 3 silver atoms.
- There is 1 gold atom.

4. **Placement of Silver Atoms (Ag)**:
- According to the problem, silver atoms are likely to occupy the tetrahedral voids.
- Since there are 8 tetrahedral voids in total, and we need to place 3 silver atoms, we can say that:
- 3 out of the 8 tetrahedral voids will be occupied by Ag atoms.

5. **Placement of Gold Atoms (Au)**:
- The gold atoms are likely to occupy the octahedral voids.
- There are 4 octahedral voids available, and since we have 1 gold atom, we can place 1 Au atom in one of the octahedral voids.

6. **Conclusion**:
- Therefore, in the alloy Cu₄Ag₃Au:
- Silver (Ag) atoms occupy 3 of the 8 tetrahedral voids.
- Gold (Au) atoms occupy 1 of the 4 octahedral voids.

### Final Answer:
- The probable locations of Ag and Au atoms are:
- **Ag occupies 3 tetrahedral voids.**
- **Au occupies 1 octahedral void.**