## Introductory Chemistry (5th Edition)

a) Number of neutrons (n) = Mass number (A)-Atomic number (Z). Given A = 59 and Z = 28. Then, $n = 59-28 = 31.$ b) $n= A-Z = 235-92 = 143$ c) In this case, A= 46 and Z = 21. $n= 46-21 = 25$ d) Here, Z = 18, A = 42. $n = A-Z = 42-18 = 24$