#### Answer

Mass number

#### Work Step by Step

This is the mass of an isotope in atomic mass units, and it is equal to the sum of the number of protons and the number of neutrons.

Published by
Cengage Learning

ISBN 10:
1285199049

ISBN 13:
978-1-28519-904-7

Mass number

You can help us out by revising, improving and updating this answer.

Update this answerAfter you claim an answer you’ll have **24 hours** to send in a draft. An editor
will review the submission and either publish your submission or provide feedback.