Question

Question #0fc8e

Answer 1

`3` atoms.

Explanation:

As its chemical formula suggests, a molecule of water contains

• two atoms of hydrogen, `2 xx "H"`
• one atom of oxygen, `1 xx "O"`

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

`"no. of atoms in H"_2"O" = "2 atoms of H + 1 atom of O"`

`"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 `"H"`. The single atom of oxygen is shown by adding the chemical symbol of oxygen without a subscript of `1`.

So instead of

`"H"_2"O"_1`

we have

`"H"_2"O"`