Name_______________________________ Date __________ Period _______ Counting Atoms Practice Determine how many atoms of each element are present: 1) CaF2 ______________________________________________________ 2) Be(OH)2 ____________________________________________________ 3) NO2 ______________________________________________________ 4) Al2(SO4)3 ___________________________________________________ 5) 3NH4NO3 ___________________________________________________ 6) S2F2 ______________________________________________________ 7) Na2CO3 ____________________________________________________ 8) 5CH4 ______________________________________________________ 9) 4CoO______________________________________________________ 10) MgSO4_____________________________________________________ Count the atoms for each of the compounds on both sides of the equation. 1. H2 + O2 2. KClO3 H2O KCl + O2 3. Na + Cl2 NaCl Think About It…. How do the equations above disobey the Law of Conservation of Matter? How can it be fixed?