How can the number of atoms of an individual element be determined by using a chemical formula?
a. dividing the atomic mass by number of atoms
b. using the subscript after each element
c. multiplying the number of atoms by their masses
d. adding all of the subscripts together after the reaction is complete.

The number of atoms of an individual element be determined by using a chemical formula is adding all of the subscripts together after the reaction is complete. The answer is letter D. The key in the balancing of chemical reaction is to make sure that you got the exact chemical formula of the substance that is reacting and the yielded product. After getting the formula, identify first the hardest element/atom to be balanced such as Na, Zn, Cl, C, O, etc. Then proceed to the easier ones such as O, H. Make sure to note the atoms present in the molecule of the substance.