## General, Organic, and Biological Chemistry: Structures of Life (5th Edition)

a) $^{202}_{80}$Hg: 80 protons, 122 neutrons, 80 electrons b) $^{127}_{53}$I: 53 protons, 74 neutrons, 53 electrons c) $^{75}_{35}$Br: 35 protons, 40 neutrons, 35 electrons d) $^{133}_{55}$Cs: 55 protons, 78 neutrons, 55 electrons e) $^{195}_{78}$Pt: 78 protons, 117 neutrons, 78 electrons
When a element is noted $^x_y$Z, then x= the mass number, which is the sum of protons and neutrons, and y=the number of protons. In a neutral atom, the number of protons always equals the number of electrons. Each of these problems are worked so that: protons=y, neutrons=(x-y), and electrons=y.