Chemistry: A Molecular Approach (3rd Edition)

Published by Prentice Hall
ISBN 10: 0321809246
ISBN 13: 978-0-32180-924-7

Chapter 2 - Sections 2.1-2.9 - Exercises - Problems by Topic - Page 80: 54a

Answer

19 protons, 21 neutrons

Work Step by Step

Atomic number of the isotope $^{40}_{19}K$ = 19 = $Z$ Mass number of $^{40}_{19}N$ = 40 = $A$ So, number of protons = Atomic number = 19 Number of neutrons = $A - Z = 40-19 $ = 21
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