Chapter 4 - The Structure of Atoms - Exercises - Atomic Composition, Isotopes, and Atomic Weights - Page 164: 18

$Sr^{84}$ contains 46 neutrons, 38 protons, and 38 electrons $Sr^{86}$ contains 48 neutrons, 38 protons, and 38 electrons $Sr^{87}$ contains 49 neutrons, 38 protons, and 38 electrons $Sr^{88}$ contains 50 neutrons, 38 protons, and 38 electrons

Sr has 38 atomic numbers which means that all Sr isotopes will have 38 protons and 38 electrons $Sr^{84}$ isotope has 84 mass number Since mass number=number of protons+number of neutrons So, Number of neutrons=massnumber-number of protons=84-38=46 neutrons $Sr^{84}$ contains 46 neutrons, 38 protons, and 38 electrons $Sr^{86}$ isotope has 86 mass number Since mass number=number of protons+number of neutrons So, Number of neutrons=massnumber-number of protons=86-38=48 neutrons $Sr^{86}$ contains 48 neutrons, 38 protons, and 38 electrons $Sr^{87}$ isotope has 87 mass number Since mass number=number of protons+number of neutrons So, Number of neutrons=massnumber-number of protons=87-38=49 neutrons $Sr^{87}$ contains 49 neutrons, 38 protons, and 38 electrons $Sr^{88}$ isotope has 88 mass number Since mass number=number of protons+number of neutrons So, Number of neutrons=massnumber-number of protons=88-38=50 neutrons $Sr^{88}$ contains 50 neutrons, 38 protons, and 38 electrons