Counting Atoms Worksheet

Counting Atoms in Chemical Formulas

Read each question carefully and follow the instructions to determine the number of atoms for each element in the given chemical formulas. Remember to consider both subscripts and coefficients.

Count the number of atoms for each element in the following chemical formulas:

1. H₂O Hydrogen:   Oxygen:  

2. CO₂ Carbon:   Oxygen:  

3. NaCl Sodium:   Chlorine:  

4. C₆H₁₂O₆ Carbon:   Hydrogen:   Oxygen:  

For formulas containing parentheses, remember to distribute the subscript outside the parentheses to all elements inside. Count the atoms for each element.

5. Mg(OH)₂ Magnesium: Oxygen: Hydrogen:

6. Ca(NO₃)₂ Calcium: Nitrogen: Oxygen:

7. How many oxygen atoms are in 3H₂O?

8. How many total atoms are in 2CH₄?

Determine the number of atoms for each element in the following formulas, considering both coefficients and subscripts:

9. 2Al₂(SO₄)₃ Aluminum:   Sulfur:   Oxygen:  

10. 3(NH₄)₃PO₄ Nitrogen:   Hydrogen:   Phosphorus:   Oxygen:  

11. Explain in your own words how to count the total number of atoms in a complex chemical formula like 4Ba₃(PO₄)₂. List the number of atoms for each element.