Two elements P and Q combine to form a compound.
If P has 2 and Q has 6 electrons in their outermosrt shell, what will be formula of the compound formed ?

Options

A. PQ
B. `P_(2)Q`
C. `P_(2)Q_(3)`
D. `PQ_(2)`

Explanation

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

### Step 1: Identify the Valence Electrons
- Element P has 2 electrons in its outermost shell.
- Element Q has 6 electrons in its outermost shell.

### Step 2: Determine the Valency of Each Element
- Element P, with 2 valence electrons, will lose these 2 electrons to achieve a stable electronic configuration (octet). Therefore, the valency of P is +2.
- Element Q, with 6 valence electrons, needs 2 more electrons to complete its octet. Thus, it will gain 2 electrons, giving it a valency of -2.

### Step 3: Write the Charges of Each Element
- The charge for P is +2 (P²⁺).
- The charge for Q is -2 (Q²⁻).

### Step 4: Use the Crisscross Method
- According to the crisscross method, we take the absolute values of the charges and use them as subscripts for the opposite element.
- For P, we take the charge of Q (2) as the subscript, and for Q, we take the charge of P (2) as the subscript.
- This gives us P₂Q₂.

### Step 5: Simplify the Formula
- The formula P₂Q₂ can be simplified by dividing both subscripts by their greatest common divisor, which is 2.
- Thus, the simplified formula is PQ.

### Final Answer
The formula of the compound formed by elements P and Q is **PQ**.

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