A compund is made of two elements `P` and `Q` are in ccp arrangement while atoms `P` occupy all the octahedral voids. What is the formula of the compound?

Explanation

To find the formula of the compound formed by elements P and Q, we can follow these steps:

### Step 1: Understand the arrangement
The problem states that the elements P and Q are in a cubic close-packed (CCP) arrangement. In a CCP structure, the number of atoms per unit cell (denoted as Z) is 4.

### Step 2: Identify the number of Q atoms
Since Q is in a CCP arrangement, the number of Q atoms in the unit cell is equal to Z, which is 4. Therefore, there are 4 Q atoms in the unit cell.

### Step 3: Determine the number of octahedral voids
In a CCP structure, the number of octahedral voids is equal to the number of atoms in the unit cell. Thus, the number of octahedral voids in the CCP structure is also 4.

### Step 4: Identify the number of P atoms
According to the problem, all the octahedral voids are occupied by P atoms. Since there are 4 octahedral voids, this means there are 4 P atoms in the unit cell.

### Step 5: Write the formula of the compound
Now that we know there are 4 P atoms and 4 Q atoms in the unit cell, we can express the formula of the compound. The ratio of P to Q is 4:4, which simplifies to 1:1. Therefore, the formula of the compound can be written as PQ.

### Final Answer
The formula of the compound is **PQ**.

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