Question

Atomicity is given by:

• A. Mass/molecular mass
• B. Mass of the element
• C. Molecular mass X atomic mass
• D. Molecular mass / atomic mass

Hint:

Atomicity is calculated as the molecular mass of the substance divided by the atomic mass of the element.

Answer 1

The Correct Option is D

• Option 1: Mass/molecular mass - This is incorrect. Atomicity is not directly calculated by dividing the mass of an element by its molecular mass. 
• Option 2: Mass of the element - This is incorrect. The atomicity is not calculated based on the mass of the element alone. Atomicity refers to the number of atoms in one molecule of the element, not its mass.
• Option 3: Molecular mass X atomic mass - This is incorrect. Atomicity is not calculated by multiplying molecular mass and atomic mass. The calculation involves dividing molecular mass by atomic mass.
• Option 4: Molecular mass / atomic mass - This is the correct answer. Atomicity is calculated by dividing the molecular mass of a compound by the atomic mass of its constituent element. This gives the number of atoms in one molecule of the element.

Explanation:

Atomicity refers to the number of atoms in one molecule of an element. It is calculated using the formula:

Atomicity = Molecular mass / Atomic mass

For example, in the case of oxygen (O₂), the molecular mass is approximately 32 g/mol, and the atomic mass of oxygen is approximately 16 g/mol. Therefore, the atomicity of oxygen is:

Atomicity = 32 / 16 = 2

This shows that one molecule of oxygen contains two oxygen atoms, so the atomicity of oxygen is 2.