Question

1. the ____________ of an element is the total number of protons and neutrons in the__________. 6. 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:

1. The mass number of an element is the sum of protons and neutrons in the nucleus of an atom.
2. The mass number helps calculate neutrons. Neutrons = Mass number - Atomic number (number of protons).

Answer:

1. mass number; nucleus
2. neutrons; atomic number; mass number