# Question #0fc8e

Jul 1, 2017

$3$ atoms.

#### Explanation:

As its chemical formula suggests, a molecule of water contains

• two atoms of hydrogen, $2 \times \text{H}$
• one atom of oxygen, $1 \times \text{O}$

This means that a single molecule of water contains a total of $3$ atoms.

$\text{no. of atoms in H"_2"O" = "2 atoms of H + 1 atom of O}$

$\text{no. of atoms in H"_2"O" = "3 atoms}$

So remember, we use subscripts to denote the number of atoms of each element present in a given compound. Keep in mind that we do not add a subscript of $1$ when dealing with a single atom.

So in this case, two atoms of hydrogen are shown by adding a subscript of $2$ after $\text{H}$. The single atom of oxygen is shown by adding the chemical symbol of oxygen without a subscript of $1$.

${\text{H"_2"O}}_{1}$
$\text{H"_2"O}$