Super! Whatever the number of atoms, we need to put that number below the name of the element. That's it!
We have been talking about atoms of different elements combining. Sometimes, atoms of the same element combine to form a molecule.

We mentioned earlier that we can't find single atoms of Oxygen (O). That is because one O atom combines with another O atom to form an O2 molecule.

Sometimes, 3 O atoms combine to form an O3 molecule. This is called Ozone.
Which of the following is correct?
  • O2 and O3 have the same properties
  • O2 and O3 have the same properties, except that O3's mass is more
  • O2 and O3 have completely different properties