Answer:
To count atoms in a molecule, add the subscripts of the molecule. Remember that if you do not see a subscript after a symbol, its subscript is 1. One molecule of water contains 3 atoms.
Explanation:
The molecular formula for water is
H
2
O
, meaning there are 2 hydrogen atoms and one oxygen atom. I found this by adding the subscripts. 2 is the subscript on hydrogen, and 1 is the subscript on oxygen, so 2 + 1 = 3 atoms total.
For example, to count the number of atoms in one molecule of glucose,
C
6
H
12
O
6
, add the subscripts, so 6+12+6 is 24 atoms. Note that
C
6
H
12
O
6
is the molecular formula of glucose, not the empirical formula.