Question

Which of the following term defines the number of atoms present in one molecule of an element?

• A. Molecularity
• B. Atomicity
• C. Vapour density
• D. Molecular mass

Answer 1

The correct option is B

Atomicity

The number of atoms present in one molecule of an element is called atomicity of the element.

E.g. N₂ + O₂ $\to$ 2 NO

Nitrogen Oxygen Nitric oxide

(1 Vol) (1 Vol) (2 Vols)

After applying Avogadro’s law, the equation becomes

N₂ + O₂ $\to$ 2 NO

1 Molecule 1 Molecule 2 Molecules

It is found that two molecules of nitric oxide contains 2 atoms of nitrogen and 2 atoms of oxygen.