Question

A water molecule contains one atom of ------------- and two atoms of --------------------

• A. Oxygen
• B. Hydrogen

Answer 1

Molecule: The smallest unit of an element or a compound consisting of a group of the same or different atoms is called a molecule.

Example: A water molecule is formed by the combination of Oxygen and Hydrogen atoms in a 2:1 (fixed) ratio.

$$\begin{gathered} 2{\mathrm{H}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{H}}_2\mathrm{O} \\ \mathrm{Hydrogen}\mathrm{Oxygen}\mathrm{Water} \\ \mathrm{molecule} \end{gathered}$$

Therefore a water molecule contains one atom of Oxygen and two atoms of Hydrogen.