Question

1. the mass number is used to calculate the number of _____________ in one atom of an element. in order to calculate the number of neutrons you must subtract the ___________ from the _____________.

Explanation:

Step1: Recall mass - number formula

The mass number ($A$) of an atom is the sum of the number of protons ($p$) and neutrons ($n$), i.e., $A=p + n$.

Step2: Rearrange for number of neutrons

To find the number of neutrons, we can rewrite the formula as $n=A - p$. So the mass number is used to calculate the number of neutrons in one atom of an element. And to calculate the number of neutrons, we subtract the atomic number (which is equal to the number of protons) from the mass number.

Answer:

neutrons; atomic number; mass number